Objective: To explore the influence of ginkgolide combined with edaravone on the brain function of elderly patients with acute cerebral infarction and its preventive effect on ischemia reperfusion injury. Methods: A t...Objective: To explore the influence of ginkgolide combined with edaravone on the brain function of elderly patients with acute cerebral infarction and its preventive effect on ischemia reperfusion injury. Methods: A total of 126 patients with acute cerebral infarction who were treated in Dazhou Central Hospital between February 2016 and May 2017 were divided into the control group (n=67) and ginkgolide group (n=59) according to different therapies. Control group received routine intravenous thrombolysis + edaravone therapy, and ginkgolide group received routine intravenous thrombolysis + edaravone + ginkgolide therapy. The differences in brain function and nerve ischemia reperfusion injury extent were compared between the two groups. Results: At T1 and T2, serum nerve function indexes NT-proBNP and NSE levels of ginkgolide group were lower than those of control group whereas BDNF levels were higher than those of control group;serum inflammatory mediators MCP-1, NF-κB, CRP and TNF-α levels were lower than those of control group;serum apoptosis molecules caspase-3 and Bax levels were lower than those of control group whereas Bcl-2 levels were higher than those of control group. Conclusion: Ginkgolide combined with edaravone therapy on the basis of intravenous thrombolysis can effectively optimize the brain function and alleviate the ischemia reperfusion injury caused by inflammatory response and apoptosisis in elderly patients with acute cerebral infarction.展开更多
This study used electroacupuncture at Renzhong （DU26） and Baihui （DU20） in a rat model of cerebral ischemia/reperfusion injury. Neurological deficit scores, western blotting, and reverse transcription-PCR results ...This study used electroacupuncture at Renzhong （DU26） and Baihui （DU20） in a rat model of cerebral ischemia/reperfusion injury. Neurological deficit scores, western blotting, and reverse transcription-PCR results demonstrated that electroacupuncture markedly reduced neurological deficits, decreased corpus striatum aquaporin-4 protein and mRNA expression, and relieved damage to the blood-brain barrier in a rat model of cerebral ischemia/reperfusion injury. These results suggest that electroacupuncture most likely protects the blood-brain barrier by regulating aquaporin-4 expression following cerebral ischemia/reperfusion injury.展开更多
BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced br...BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced brain edema remain poorly understood.OBJECTIVE：To establish a newborn animal model of astrocytic oxygen-glucose deprivation and reintroduction,to observe the correlation between AQP4 and cellular volume,and to investigate the role of AQP4 in the development of brain edema following oxygen deprivation and reintroduction.DESIGN,TIME AND SETTING：A comparative experiment was performed at the Experimental Center of West China Second University Hospital between October 2007 and April 2009.MATERIALS：Astrocytes were derived from the neocortex of Sprague Dawley rats aged 3 days.METHODS：Astrocytes were incubated in glucose/serum-free Dulbecco＇s modified Eagle＇s medium,followed by 1% oxygen for 6 hours.Finally,oxygen-glucose deprivation and reintroduction models were successfully established.MAIN OUTCOME MEASURES：Real-time polymerase chain reaction and Western blot analysis were used to measure expression of AQP4 mRNA and protein in cultured rat astrocytes following oxygen-glucose deprivation and reintroduction.Astrocytic cellular volume,as determined by [3H]-3-O-methyl-D-glucose,was used to represent the extent of astrocytic swelling.RESULTS：During oxygen-glucose deprivation,AQP4 mRNA and protein expression gradually decreased in astrocytes,whereas cellular volume increased in a time-dependent manner （P〈 0.01）.Following oxygen-glucose reintroduction,AQP4 mRNAand protein expression was upregulated,peaked at day 7,and then gradually decreased,but still higher than normal levels （P 〈 0.05）.However,cellular volume gradually decreased （P 〈 0.01）,and then reached normal levels at day 7.CONCLUSION：AQP4 expression highly correlated with cellular volume changes,suggesting that AQP4 played an important role in modulating brain water transport in an astrocytic oxygen-glucose deprivation and reintroduction model.展开更多
Despite obvious progress in the treatment of acute forms of ischemic stroke, the risk of this condition remains unacceptably high. Brain infarction in the middle cerebral artery basin occurs in patients with atheroscl...Despite obvious progress in the treatment of acute forms of ischemic stroke, the risk of this condition remains unacceptably high. Brain infarction in the middle cerebral artery basin occurs in patients with atherosclerosis. The onset of the brain infarction is facilitated by the cessation of circulation (embolism) in conditions of insufficient collateral circulation. The extent of the infarct zone is determined by neuronal death and impaired microcirculation. The development of new methods for effective targeted restorative stroke therapy is crucial for restorative treatment and reducing the risk of mortality after stroke. Remote ischemic conditioning (RIC) is an approach to limiting reperfusion injury in the ischemic region of the brain after focal ischemia. One of the most commonly used <i>in vivo</i> models in stroke studies is the filament model of Middle Cerebral Artery Occlusion (MCAO) in rats. In our experiment, it was performed for 30 min (J. Koizumi) with subsequent 48-hour reperfusion. Within the first 24 hours after the start of reperfusion several short episodes of ischemia in low limbs were induced. After 48 hours of reperfusion the brains were harvested and stained with TTC. Then we evaluated the effect of RIC within 24 hours <i>ex vivo</i> in rats’ brains, as well as syndecan-1 plasma concentration. Infarct area was assessed by means of Image-Pro program with statistical analysis. Infarct volumes in the model group (31.97% ± 2.5%) were significantly higher compared to the values in the RIC group 48 hours after ischemia-reperfusion (13.6% ± 1.3%) (*P < 0.05). A significant reduction in the area of infarction after RIC is likely due to the effect on the regulation of collateral blood flow in the ischemia area. On the second day after ischemia-reperfusion, tissue swelling was reduced in the RIC group compared to the model group. Analysis of the average concentration of Syndecan-1 revealed the difference between model and RIC groups. Syndecan-1, endothelial glycocalyx protein, might be the regulator which performs vascular control of the interaction with inflammatory cell and is responsible for mediate effect of remote ischemic conditioning on the restriction of ischemic-reperfusion injury.展开更多
Many therapies with potential for treatment of brain injury have been investigated. Few types of cells have spurred as much interest and excitement as stem cells over the past few decades. The multipotentiality and se...Many therapies with potential for treatment of brain injury have been investigated. Few types of cells have spurred as much interest and excitement as stem cells over the past few decades. The multipotentiality and self-renewing characteristics of stem cells confer upon them the capability to regenerate lost tissue in ischemic or degenerative conditions as well as trauma. While stem cells have not yet proven to be clinically effective in many such conditions as was once hoped, they have demonstrated some effects that could be manipulated for clinical benefit. The various types of stem cells have similar characteristics, and largely differ in terms of origin; those that have differentiated to some extent may exhibit limited capability in differentiation potential. Stem cells can aid in decreasing lesion size and improving function following brain injury.展开更多
In this study, we hypothesized that an increase in integrin αβand its co-activator vascular endothelial growth factor play important neuroprotective roles in ischemic injury. We performed ischemic preconditioning wi...In this study, we hypothesized that an increase in integrin αβand its co-activator vascular endothelial growth factor play important neuroprotective roles in ischemic injury. We performed ischemic preconditioning with bilateral common carotid artery occlusion for 5 minutes in C57BL/6J mice. This was followed by ischemic injury with bilateral common carotid artery occlusion for 30 minutes. The time interval between ischemic preconditioning and lethal ischemia was 48 hours. Histopathological analysis showed that ischemic preconditioning substantially diminished damage to neurons in the hippocampus 7 days after ischemia. Evans Blue dye assay showed that ischemic preconditioning reduced damage to the blood-brain barrier 24 hours after ischemia. This demonstrates the neuroprotective effect of ischemic preconditioning. Western blot assay revealed a significant reduction in protein levels of integrin αβ, vascular endothelial growth factor and its receptor in mice given ischemic preconditioning compared with mice not given ischemic preconditioning 24 hours after ischemia. These findings suggest that the neuroprotective effect of ischemic preconditioning is associated with lower integrin αβand vascular endothelial growth factor levels in the brain following ischemia.展开更多
Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic pre- conditioning in rats by simulating a...Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic pre- conditioning in rats by simulating a transient ischemic attack twice （each a 20-minute occlusion of the middle cerebral artery） before inducing focal cerebral infarction （2 hour occlusion-reper- fusion in the same artery）. We also explored the mechanism underlying the neuroprotective effect of ischemic preconditioning. Seven days after ocdusion-reperfusion, tetrazolium chloride staining and immunohistochemistry revealed that the infarct volume was significantly smaller in the group that underwent preconditioning than in the model group. Furthermore, vascular endothelial growth factor immunoreactivity was considerably greater in the hippocampal CA3 region of preconditioned rats than model rats. Our results suggest that the protective effects of ischemic preconditioning on focal cerebral infarction are associated with upregulation of vascu- lar endothelial growth factor.展开更多
Auditory evoked magnetic fields were recorded from 15 patients with acute cerebral infarction and 11 healthy volunteers using magnetoencephalography.The auditory stimuli of 2 kHz pure tone were binaurally presented wi...Auditory evoked magnetic fields were recorded from 15 patients with acute cerebral infarction and 11 healthy volunteers using magnetoencephalography.The auditory stimuli of 2 kHz pure tone were binaurally presented with an interstimulus interval of 1 second.The intensity of stimuli was 90 dB and the stimulus duration was 8 ms.The results showed that the M100 was the prominent response, peaking approximately 100 ms after stimulus onset in all subjects.It originated from the area close to Heschl’s gyrus.In the patient group,the peak latency of M100 responses was significantly prolonged,and the mean strength of equivalent current dipole was significantly smaller in the affected hemisphere.The three-dimensional inter-hemispheric difference of the M100 positions was increased in the patient group.Our experimental findings suggested that impairment of cerebral function in patients with acute ischemic stroke can be detected using magnetoencephalography with the higher spatial resolution and temporal resolution.Magnetoencephalography could provide objective and sensitive indices to estimate auditory cortex function in patients with acute cerebral infarction.展开更多
Previous studies have focused on the analysis of single or several function-related genes in oxidative stress; however, little information is available regarding altered expression of oxidative stress-related genes in...Previous studies have focused on the analysis of single or several function-related genes in oxidative stress; however, little information is available regarding altered expression of oxidative stress-related genes in the process of ischemia-reperfusion injury from microarray experiments. The aim of the present study was to investigate the changes in cell oxidative stress- and toxicity-related gene expression utilizing microarray screening in patients with acute cerebral infarction during cerebral ischemia-reperfusion injury. Of the included 114 genes, expression was significantly upregulated in eight genes, including three heat shock protein-related genes, one oxidative and metabolic stress-related gene, one cell growth arrest/senescence related gene, two apoptosis signal-related genes, and one DNA damage and repair related gene. Expression was significantly downregulated in four genes, including one cell proliferation/cancer related gene, two oxidative and metabolic stress-related genes and one DNA damage and repair related gene. The results demonstrated that cerebral ischemia-reperfusion injury in patients with acute cerebral infarction was affected by many genes including oxidative stress-, heat shock-, DNA damage and repair-, and apoptosis signal-related genes. Therefore, it could be suggested that cerebral ischemia-reperfusion injury may be subjected to complex genetic regulation mechanisms.展开更多
A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of th...A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection.展开更多
BACKGROUND： Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influe...BACKGROUND： Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influence of electro-acupuncture at the Du meridian on neural stem cell proliferation. OBJECTIVE： To observe the influence of electro-acupuncture at Ren and Du meridians on neural stem cell proliferation in the subventricular zone and altered signal transduction in cerebral ischemia rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Human Anatomy, Medical College of Sun Yat-sen University from May 2006 to February 2008. MATERIALS： Mouse anti-rat bromodeoxyuridine （BrdU） monoclonal antibody was provided by Sigma, USA; mouse anti-rat nestin monoclonal antibody and extracellular signal-regulated protein kinase （ERK） specific inhibitor PD98059 were provided by Calbiochem, Germany; acupuncture needle was provided by Suzhou Acupuncture Supplies, China. METHODS： A total of 126 rats were randomly assigned to four groups： model （n = 36）, Du meridian （n = 36）, Ren/Du meridian （n = 36）, and Ren/Du meridian ＋ PD98059 （n = 18）. Rats in the Ren/Du meridian ＋ PD98059 group were observed on days 7 （n = 6） and 14 （n = 12） after cerebral ischemia injury. Rats in the model, Du meridian, and Ren/Du meridian groups were observed on days 7, 14, and 28 after cerebral ischemia injury, with 12 rats per group at each time point. Thread occlusion was used to establish middle cerebral artery occlusion models. Electro-acupuncture was performed at Renzhong （DU 26） and Baihui （DU 20） acupoints in the Du meridian group, as well as Chengjiang （RN 24）, Guanyuan （RN 4）, Renzhong, and Baihuiacupoints in the Ren/Du meridian and Ren/Du meridian ＋ PD98059 groups 2 days after model establishment. In addition, electro-acupuncture stimulation with disperse-dense waves was performed, with 30 Hz disperse wave, 100 Hz dense wave, and 5 V intensity for 20 minutes. Rats in the Ren/Du meridian ＋ PD98059 group were treated with 0.2 pg PD98059 injection into the subventricular zone, 2 pL per rat. Rats in the model group were not treated with electro-acupuncture. MAIN OUTCOME MEASURES： BrdU/nestin immunofluorescent staining was used to detect proliferating neural stem cells in the subventricular zone of cerebral ischemia rats; Western blot was used to determine phosphorylated ERK1 and 2 （pERK1/2） expression in the subventricular zone. RESULTS： On days 14 and 28 after cerebral ischemia, there were significantly more BrdU-positive and BrdU/nestin-positive cells in the Ren/Du meridian group compared with the Du meridian group （P 〈 0.05）. PD98059 decreased the number of BrdU-positive and BrdU/nestin-positive cells induced by electro-acupuncture at the/：ten and Du meridians （P 〈 0.05）. On days 7, 14, and 28 after treatment, pERK1/2 expression was significantly greater in the Du meridian and Ren/Du meridian groups compared with the model group （P 〈 0.05）. The promoting effect of electro-acupuncture at Ren and Du meridians on ERK1/2 phosphorylation was superior to electro-acupuncture at the Du meridian alone on day 14 after model induction （P 〈 0.05）. However, PD98059 completely abolished the promoting effect of electro-acupuncture at Ren/Du meridians on pERK1/2 expression （P 〈 0.05）. CONCLUSION： Electro-acupuncture at Ren and Du meridians increased proliferation of subventricular zone neural stem cells, which was related to activation of the ERK pathway in a rat model of cerebral ischemia injury.展开更多
13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inflammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous...13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inflammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous system. We investigated whether these properties of 13-methyltetradecanoic acid have a neuroprotective effect on focal cerebral ischemia/reperfusion injury, and detected the expression of basic fibroblast growth factor and vascular endothelial growth factor. This study established rat models of middle cerebral artery occlusion/ reperfusion injury by ischemia for 2 hours and reperfusion for 24 hours. At the beginning of reperfusion, 13-methyltetradecanoic acid 10, 40 or 80 mg/kg was injected into the tail vein. Results found that various doses of 13-methyltetradecanoic acid effectively reduced infarct volume, mitigate cerebral edema, and increased the mRNA and protein expression of basic fibroblast growth factor and vascular endothe- lial growth factor at 24 hours of reperfusion. The effect was most significant in the 13-methyltetradecanoic acid 40 and 80 mg/kg groups. The findings suggest that 13-methyltetradecanoic acid can relieve focal ischemia/reperfusion injury immediately after reperfusion, stimu- late the upregulation of basic fibroblast growth factor and vascular endothelial growth factor to exert neuroprotective effects.展开更多
Neonatal hypoxic-ischemic encephalopathy is a serious neurological disease,often resulting in long-term neurodevelopmental disorders among surviving children.However,whether these neurodevelopmental issues can be pass...Neonatal hypoxic-ischemic encephalopathy is a serious neurological disease,often resulting in long-term neurodevelopmental disorders among surviving children.However,whether these neurodevelopmental issues can be passed to offspring remains unclear.The right common carotid artery of 7-day-old parental-generation rats was subjected to permanent ligation using a vessel electrocoagulator.Neonatal hypoxic-ischemic rat models were established by subjecting the rats to 8%O2–92%N2 for 2 hours.The results showed that 24 hours after hypoxia and ischemia,pathological damage,cerebral atrophy,liquefaction,and impairment were found,and Zea-Longa scores were significantly increased.The parental-generation rats were propagated at 3 months old,and offspring were obtained.No changes in the overall brain structures of these offspring rats were identified by magnetic resonance imaging.However,the escape latency was longer and the number of platform crossings was reduced among these offspring compared with normal rats.These results indicated that the offspring of hypoxic-ischemic encephalopathy model rats displayed cognitive impairments in learning and memory.This study was approved by the Animal Care&Welfare Committee of Kunming Medical University,China in 2018(approval No.kmmu2019072).展开更多
This study aimed to investigate changes in secretory pathway Ca2＋-ATPase 2 expression following cerebral ischemia/reperfusion injury, and to define the role of Ca2＋-ATPases in oxidative stress. A rat model of cerebr...This study aimed to investigate changes in secretory pathway Ca2＋-ATPase 2 expression following cerebral ischemia/reperfusion injury, and to define the role of Ca2＋-ATPases in oxidative stress. A rat model of cerebral ischemia/reperfusion injury was established using the unilateral middle cerebral artery occlusion method. Immunohistochemistry and reverse transcription-PCR assay results showed that compared with the control group, the expression of secretory pathway Ca2＋-ATPase 2 protein and mRNA in the cerebral cortex and hippocampus of male rats did not significantly change during the ischemic period. However, secretory pathway Ca2＋-ATPase 2 protein and mRNA expression reduced gradually at 1, 3, and 24 hours during the reperfusion period. Our experimental findings indicate that levels of secretory pathway Ca2＋-ATPase 2 protein and mRNA expression in brain tissue change in response to cerebral ischemia/reperfusion injury.展开更多
BACKGROUND： Previous studies of cerebral ischemia have used young animals, with an ischemic time greater than 5 minutes （safe time limit）. Despite an increased understanding of neuronal apoptosis, it remains uncert...BACKGROUND： Previous studies of cerebral ischemia have used young animals, with an ischemic time greater than 5 minutes （safe time limit）. Despite an increased understanding of neuronal apoptosis, it remains uncertain whether brief cerebral ischemic events of 5 minutes or less damage brain tissue in elderly rodents. OBJECTIVE： To investigate the effects of transient cerebral ischemia （5 minutes）/reperfusion injury on brain cortical and hippocampal edema, aquaporin-4 （AQP-4） expression, and neuronal apoptosis in aged rats, and to compare ischemic sensitivity between cortex and hippocampus. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Institute of Cerebrovascular Disease, Qingdao University Medical School from April 2008 to March 2009. MATERIALS： Rabbit anti-AQP-4 polyclonal antibody, TUNEL kit, and SABC immunohistochemistry kit were purchased from Wuhan Boster Bioengineering, China. METHODS： A total of 160 healthy, male, aged 19-21 months, Wistar rats were randomly assigned to 4 groups： sham-surgery, and ischemia 1-, 3-, and 5-minute groups, with 40 rats in each group. The global cerebral ischemia model was established using the Pusinelli four-vessel occlusion, and the three cerebral ischemia groups were subdivided into reperfusion 12-hour, 1-, 2-, 3-, and 7-day subgroups, with 8 rats in each subgroup. The sham-surgery group was subjected to exposure of the first cervical bilateral alar foramina and bilateral common carotid arteries. MAIN OUTCOME MEASURES： The dry-wet weight assay was used to measure brain water content and histopathology of the cortex and hippocampus was observed following hematoxylin-eosin staining. In addition, cortical and hippocampal AQP-4 expression was detected by streptavidin-biotin complex immunohistochemistry, and neuronal apoptosis was detected by the TUNEL method. RESULTS： There was no significant difference in brain water content or AQP-4 expression in the cortex and hippocampus between ischemia 1- and 3-minute groups and the sham-surgery group or brain water content or AQP-4 expression in the cortex between ischemia 5-minute group and sham-surgery group （P 〉 0.05）. However, brain water content and AQP-4 expression in the hippocampus after 5 minutes of cerebral ischemia were significantly increased compared with the sham-surgery group （P 〈 0.05 or P 〈 0.01）. Several TUNEL-positive cells were observed in the cortex and hippocampus of the sham-surgery group and ischemia 1-minute group, as well as in the cortex of the ischemia 3-minute group. In addition, the number of apoptotic neurons in the hippocampus of ischemia 3-minute group and in the cortex and hippocampus of ischemia 5-minute group was significantly increased （P 〈 0.05 or P 〈 0.01 ）. Neuronal apoptosis was increased after 12 hours of ischemia/reperfusion, and it reached a peak by 2 days （P 〈 0.01）. CONCLUSION： Transient cerebral ischemia （5 minutes） resulted in increased hippocampal edema, AQP-4 expression, and neuronal apoptosis. Moreover, cerebral ischemia had a greater effect on neuronal apoptosis than brain edema or AQP-4 expression, and the hippocampus was more sensitive than the cortex.展开更多
Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by ...Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage.The mechanisms underlying exacerbated hemorrhage are not fully understood.This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy.The results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+mice.This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion.This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEGF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEGF up-regulation,resulting in rapid vessel disintegration in diabetic stroke.Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions.In conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation.Thus,suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window.Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong[CULATR 3834-15(approval date January 5,2016);3977-16(approval date April 13,2016);and 4666-18(approval date March 29,2018)].展开更多
Objective： To determine whether AQP4 expression is associated with lactate （Lac） and Nacetyl aspartate （NAA） and with apparent diffusion coefficient （ADC） abnormality after rat cerebral ischemia. Methods： The ...Objective： To determine whether AQP4 expression is associated with lactate （Lac） and Nacetyl aspartate （NAA） and with apparent diffusion coefficient （ADC） abnormality after rat cerebral ischemia. Methods： The time courses of ADC and lactate and NAA assessed by proton magnetic resonance spectroscopy （^1HMRS） were investigated at the time point of 6 h, and 1, 3, 7 d after rat cerebral ischernia induced by middle cerebral artery occlusion. Expression of AQP4 mRNA and protein were measured using RT-PCR and Western blot analysis respectively. Results： Significant reductions of NAA concentration and increases of lactate concentration were found after rat cerebral ischemia. The expressions of AQP4 mRNA t and protein were increased at 6 h, and reached the peak at 1-3 d, then began to decrease at 7 d after rat cerebral ischemia. The expression of AQP4 was significantly correlated with NAA （rRT = -0. 856, rw = -0. 927, P〈0.01）, and with lactate （rw=0. 473, rRT=0. 413, P〈0.05）, and with ADC values during the period of 1-7d after rat cerebralischemia （rw=0.984, rRT=0.925, P〈0.05）. In addition, correlations between Lac and the ADC values（r=-0. 677, P〈0.05）and between NAA and ADC values during the period of 1-7 d after rat cerebralischemia （r=0.909, P（0.05） were also observed. Conclusion： The data suggest that AQP4 is involved in the transport of water when brain edema is formed and cell membrane integrity is lost.展开更多
文摘Objective: To explore the influence of ginkgolide combined with edaravone on the brain function of elderly patients with acute cerebral infarction and its preventive effect on ischemia reperfusion injury. Methods: A total of 126 patients with acute cerebral infarction who were treated in Dazhou Central Hospital between February 2016 and May 2017 were divided into the control group (n=67) and ginkgolide group (n=59) according to different therapies. Control group received routine intravenous thrombolysis + edaravone therapy, and ginkgolide group received routine intravenous thrombolysis + edaravone + ginkgolide therapy. The differences in brain function and nerve ischemia reperfusion injury extent were compared between the two groups. Results: At T1 and T2, serum nerve function indexes NT-proBNP and NSE levels of ginkgolide group were lower than those of control group whereas BDNF levels were higher than those of control group;serum inflammatory mediators MCP-1, NF-κB, CRP and TNF-α levels were lower than those of control group;serum apoptosis molecules caspase-3 and Bax levels were lower than those of control group whereas Bcl-2 levels were higher than those of control group. Conclusion: Ginkgolide combined with edaravone therapy on the basis of intravenous thrombolysis can effectively optimize the brain function and alleviate the ischemia reperfusion injury caused by inflammatory response and apoptosisis in elderly patients with acute cerebral infarction.
基金funded by the National NaturalScience Foundation of China (Youth), No. 81001556
文摘This study used electroacupuncture at Renzhong （DU26） and Baihui （DU20） in a rat model of cerebral ischemia/reperfusion injury. Neurological deficit scores, western blotting, and reverse transcription-PCR results demonstrated that electroacupuncture markedly reduced neurological deficits, decreased corpus striatum aquaporin-4 protein and mRNA expression, and relieved damage to the blood-brain barrier in a rat model of cerebral ischemia/reperfusion injury. These results suggest that electroacupuncture most likely protects the blood-brain barrier by regulating aquaporin-4 expression following cerebral ischemia/reperfusion injury.
基金the National Natural Science Foundation of China,No.30825039,30973236,30872346,30770748Chinese Postdoctoral Training Grant,No. 20070420575+1 种基金Application Basic Research Foundation of Sichuan Province,No. 2008JY0131Youth Science and Technology Foundation of Sichuan Province,No. 07zq026-135
文摘BACKGROUND：Previous studies have demonstrated that aquaporin-4 （AQP4） plays a key role in the formation and resolution of brain edema.However,the molecular mechanisms and role of AQP4 in hypoxia-ischemia-induced brain edema remain poorly understood.OBJECTIVE：To establish a newborn animal model of astrocytic oxygen-glucose deprivation and reintroduction,to observe the correlation between AQP4 and cellular volume,and to investigate the role of AQP4 in the development of brain edema following oxygen deprivation and reintroduction.DESIGN,TIME AND SETTING：A comparative experiment was performed at the Experimental Center of West China Second University Hospital between October 2007 and April 2009.MATERIALS：Astrocytes were derived from the neocortex of Sprague Dawley rats aged 3 days.METHODS：Astrocytes were incubated in glucose/serum-free Dulbecco＇s modified Eagle＇s medium,followed by 1% oxygen for 6 hours.Finally,oxygen-glucose deprivation and reintroduction models were successfully established.MAIN OUTCOME MEASURES：Real-time polymerase chain reaction and Western blot analysis were used to measure expression of AQP4 mRNA and protein in cultured rat astrocytes following oxygen-glucose deprivation and reintroduction.Astrocytic cellular volume,as determined by [3H]-3-O-methyl-D-glucose,was used to represent the extent of astrocytic swelling.RESULTS：During oxygen-glucose deprivation,AQP4 mRNA and protein expression gradually decreased in astrocytes,whereas cellular volume increased in a time-dependent manner （P〈 0.01）.Following oxygen-glucose reintroduction,AQP4 mRNAand protein expression was upregulated,peaked at day 7,and then gradually decreased,but still higher than normal levels （P 〈 0.05）.However,cellular volume gradually decreased （P 〈 0.01）,and then reached normal levels at day 7.CONCLUSION：AQP4 expression highly correlated with cellular volume changes,suggesting that AQP4 played an important role in modulating brain water transport in an astrocytic oxygen-glucose deprivation and reintroduction model.
文摘Despite obvious progress in the treatment of acute forms of ischemic stroke, the risk of this condition remains unacceptably high. Brain infarction in the middle cerebral artery basin occurs in patients with atherosclerosis. The onset of the brain infarction is facilitated by the cessation of circulation (embolism) in conditions of insufficient collateral circulation. The extent of the infarct zone is determined by neuronal death and impaired microcirculation. The development of new methods for effective targeted restorative stroke therapy is crucial for restorative treatment and reducing the risk of mortality after stroke. Remote ischemic conditioning (RIC) is an approach to limiting reperfusion injury in the ischemic region of the brain after focal ischemia. One of the most commonly used <i>in vivo</i> models in stroke studies is the filament model of Middle Cerebral Artery Occlusion (MCAO) in rats. In our experiment, it was performed for 30 min (J. Koizumi) with subsequent 48-hour reperfusion. Within the first 24 hours after the start of reperfusion several short episodes of ischemia in low limbs were induced. After 48 hours of reperfusion the brains were harvested and stained with TTC. Then we evaluated the effect of RIC within 24 hours <i>ex vivo</i> in rats’ brains, as well as syndecan-1 plasma concentration. Infarct area was assessed by means of Image-Pro program with statistical analysis. Infarct volumes in the model group (31.97% ± 2.5%) were significantly higher compared to the values in the RIC group 48 hours after ischemia-reperfusion (13.6% ± 1.3%) (*P < 0.05). A significant reduction in the area of infarction after RIC is likely due to the effect on the regulation of collateral blood flow in the ischemia area. On the second day after ischemia-reperfusion, tissue swelling was reduced in the RIC group compared to the model group. Analysis of the average concentration of Syndecan-1 revealed the difference between model and RIC groups. Syndecan-1, endothelial glycocalyx protein, might be the regulator which performs vascular control of the interaction with inflammatory cell and is responsible for mediate effect of remote ischemic conditioning on the restriction of ischemic-reperfusion injury.
基金supported by research grants R01 HL112597,R01 HL116042,and R01 HL120659(to DKA)
文摘Many therapies with potential for treatment of brain injury have been investigated. Few types of cells have spurred as much interest and excitement as stem cells over the past few decades. The multipotentiality and self-renewing characteristics of stem cells confer upon them the capability to regenerate lost tissue in ischemic or degenerative conditions as well as trauma. While stem cells have not yet proven to be clinically effective in many such conditions as was once hoped, they have demonstrated some effects that could be manipulated for clinical benefit. The various types of stem cells have similar characteristics, and largely differ in terms of origin; those that have differentiated to some extent may exhibit limited capability in differentiation potential. Stem cells can aid in decreasing lesion size and improving function following brain injury.
基金supported by grants from the National Natural Science Foundation of China,No.81071068the Israel Science Foundation-the National Natural Science Foundation of China(Joint Program),No.813111290the Natural Science Foundation of Guangdong Province in China,No.2014A030313172
文摘In this study, we hypothesized that an increase in integrin αβand its co-activator vascular endothelial growth factor play important neuroprotective roles in ischemic injury. We performed ischemic preconditioning with bilateral common carotid artery occlusion for 5 minutes in C57BL/6J mice. This was followed by ischemic injury with bilateral common carotid artery occlusion for 30 minutes. The time interval between ischemic preconditioning and lethal ischemia was 48 hours. Histopathological analysis showed that ischemic preconditioning substantially diminished damage to neurons in the hippocampus 7 days after ischemia. Evans Blue dye assay showed that ischemic preconditioning reduced damage to the blood-brain barrier 24 hours after ischemia. This demonstrates the neuroprotective effect of ischemic preconditioning. Western blot assay revealed a significant reduction in protein levels of integrin αβ, vascular endothelial growth factor and its receptor in mice given ischemic preconditioning compared with mice not given ischemic preconditioning 24 hours after ischemia. These findings suggest that the neuroprotective effect of ischemic preconditioning is associated with lower integrin αβand vascular endothelial growth factor levels in the brain following ischemia.
文摘Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic pre- conditioning in rats by simulating a transient ischemic attack twice （each a 20-minute occlusion of the middle cerebral artery） before inducing focal cerebral infarction （2 hour occlusion-reper- fusion in the same artery）. We also explored the mechanism underlying the neuroprotective effect of ischemic preconditioning. Seven days after ocdusion-reperfusion, tetrazolium chloride staining and immunohistochemistry revealed that the infarct volume was significantly smaller in the group that underwent preconditioning than in the model group. Furthermore, vascular endothelial growth factor immunoreactivity was considerably greater in the hippocampal CA3 region of preconditioned rats than model rats. Our results suggest that the protective effects of ischemic preconditioning on focal cerebral infarction are associated with upregulation of vascu- lar endothelial growth factor.
基金supported by the Technology Foundation for a Selected Overseas Chinese Scholar,Ministryof Human Resources and Social Security of China,No.2009-11-6the Natural Science Foundation of HebeiProvince of China,No.C2009001483
文摘Auditory evoked magnetic fields were recorded from 15 patients with acute cerebral infarction and 11 healthy volunteers using magnetoencephalography.The auditory stimuli of 2 kHz pure tone were binaurally presented with an interstimulus interval of 1 second.The intensity of stimuli was 90 dB and the stimulus duration was 8 ms.The results showed that the M100 was the prominent response, peaking approximately 100 ms after stimulus onset in all subjects.It originated from the area close to Heschl’s gyrus.In the patient group,the peak latency of M100 responses was significantly prolonged,and the mean strength of equivalent current dipole was significantly smaller in the affected hemisphere.The three-dimensional inter-hemispheric difference of the M100 positions was increased in the patient group.Our experimental findings suggested that impairment of cerebral function in patients with acute ischemic stroke can be detected using magnetoencephalography with the higher spatial resolution and temporal resolution.Magnetoencephalography could provide objective and sensitive indices to estimate auditory cortex function in patients with acute cerebral infarction.
基金the National Natural Science Foundation of China,No.30070829
文摘Previous studies have focused on the analysis of single or several function-related genes in oxidative stress; however, little information is available regarding altered expression of oxidative stress-related genes in the process of ischemia-reperfusion injury from microarray experiments. The aim of the present study was to investigate the changes in cell oxidative stress- and toxicity-related gene expression utilizing microarray screening in patients with acute cerebral infarction during cerebral ischemia-reperfusion injury. Of the included 114 genes, expression was significantly upregulated in eight genes, including three heat shock protein-related genes, one oxidative and metabolic stress-related gene, one cell growth arrest/senescence related gene, two apoptosis signal-related genes, and one DNA damage and repair related gene. Expression was significantly downregulated in four genes, including one cell proliferation/cancer related gene, two oxidative and metabolic stress-related genes and one DNA damage and repair related gene. The results demonstrated that cerebral ischemia-reperfusion injury in patients with acute cerebral infarction was affected by many genes including oxidative stress-, heat shock-, DNA damage and repair-, and apoptosis signal-related genes. Therefore, it could be suggested that cerebral ischemia-reperfusion injury may be subjected to complex genetic regulation mechanisms.
基金sponsored by the Open Research Fund of Zhejiang First-foremost Key Subject-Acupuncture & Moxibustion,No. ZTK2010A07
文摘A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection.
基金the National Natural Science Foundation of China,No.30371808the Natural Science Foundation of Guangdong Province,No.5009688
文摘BACKGROUND： Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influence of electro-acupuncture at the Du meridian on neural stem cell proliferation. OBJECTIVE： To observe the influence of electro-acupuncture at Ren and Du meridians on neural stem cell proliferation in the subventricular zone and altered signal transduction in cerebral ischemia rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Human Anatomy, Medical College of Sun Yat-sen University from May 2006 to February 2008. MATERIALS： Mouse anti-rat bromodeoxyuridine （BrdU） monoclonal antibody was provided by Sigma, USA; mouse anti-rat nestin monoclonal antibody and extracellular signal-regulated protein kinase （ERK） specific inhibitor PD98059 were provided by Calbiochem, Germany; acupuncture needle was provided by Suzhou Acupuncture Supplies, China. METHODS： A total of 126 rats were randomly assigned to four groups： model （n = 36）, Du meridian （n = 36）, Ren/Du meridian （n = 36）, and Ren/Du meridian ＋ PD98059 （n = 18）. Rats in the Ren/Du meridian ＋ PD98059 group were observed on days 7 （n = 6） and 14 （n = 12） after cerebral ischemia injury. Rats in the model, Du meridian, and Ren/Du meridian groups were observed on days 7, 14, and 28 after cerebral ischemia injury, with 12 rats per group at each time point. Thread occlusion was used to establish middle cerebral artery occlusion models. Electro-acupuncture was performed at Renzhong （DU 26） and Baihui （DU 20） acupoints in the Du meridian group, as well as Chengjiang （RN 24）, Guanyuan （RN 4）, Renzhong, and Baihuiacupoints in the Ren/Du meridian and Ren/Du meridian ＋ PD98059 groups 2 days after model establishment. In addition, electro-acupuncture stimulation with disperse-dense waves was performed, with 30 Hz disperse wave, 100 Hz dense wave, and 5 V intensity for 20 minutes. Rats in the Ren/Du meridian ＋ PD98059 group were treated with 0.2 pg PD98059 injection into the subventricular zone, 2 pL per rat. Rats in the model group were not treated with electro-acupuncture. MAIN OUTCOME MEASURES： BrdU/nestin immunofluorescent staining was used to detect proliferating neural stem cells in the subventricular zone of cerebral ischemia rats; Western blot was used to determine phosphorylated ERK1 and 2 （pERK1/2） expression in the subventricular zone. RESULTS： On days 14 and 28 after cerebral ischemia, there were significantly more BrdU-positive and BrdU/nestin-positive cells in the Ren/Du meridian group compared with the Du meridian group （P 〈 0.05）. PD98059 decreased the number of BrdU-positive and BrdU/nestin-positive cells induced by electro-acupuncture at the/：ten and Du meridians （P 〈 0.05）. On days 7, 14, and 28 after treatment, pERK1/2 expression was significantly greater in the Du meridian and Ren/Du meridian groups compared with the model group （P 〈 0.05）. The promoting effect of electro-acupuncture at Ren and Du meridians on ERK1/2 phosphorylation was superior to electro-acupuncture at the Du meridian alone on day 14 after model induction （P 〈 0.05）. However, PD98059 completely abolished the promoting effect of electro-acupuncture at Ren/Du meridians on pERK1/2 expression （P 〈 0.05）. CONCLUSION： Electro-acupuncture at Ren and Du meridians increased proliferation of subventricular zone neural stem cells, which was related to activation of the ERK pathway in a rat model of cerebral ischemia injury.
基金supported by grants from of the Science and Technology Project of Fujian Province of China,No.2010Y0027the Professor Development Fund of Fujian Medical University of China,No.JS12001
文摘13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inflammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous system. We investigated whether these properties of 13-methyltetradecanoic acid have a neuroprotective effect on focal cerebral ischemia/reperfusion injury, and detected the expression of basic fibroblast growth factor and vascular endothelial growth factor. This study established rat models of middle cerebral artery occlusion/ reperfusion injury by ischemia for 2 hours and reperfusion for 24 hours. At the beginning of reperfusion, 13-methyltetradecanoic acid 10, 40 or 80 mg/kg was injected into the tail vein. Results found that various doses of 13-methyltetradecanoic acid effectively reduced infarct volume, mitigate cerebral edema, and increased the mRNA and protein expression of basic fibroblast growth factor and vascular endothe- lial growth factor at 24 hours of reperfusion. The effect was most significant in the 13-methyltetradecanoic acid 40 and 80 mg/kg groups. The findings suggest that 13-methyltetradecanoic acid can relieve focal ischemia/reperfusion injury immediately after reperfusion, stimu- late the upregulation of basic fibroblast growth factor and vascular endothelial growth factor to exert neuroprotective effects.
基金supported by the National Natural Science Foundation of China,No.81560215(FW)the Innovative Research Team Program of Science and Technology in Yunnan Province of China,No.2017HC007
文摘Neonatal hypoxic-ischemic encephalopathy is a serious neurological disease,often resulting in long-term neurodevelopmental disorders among surviving children.However,whether these neurodevelopmental issues can be passed to offspring remains unclear.The right common carotid artery of 7-day-old parental-generation rats was subjected to permanent ligation using a vessel electrocoagulator.Neonatal hypoxic-ischemic rat models were established by subjecting the rats to 8%O2–92%N2 for 2 hours.The results showed that 24 hours after hypoxia and ischemia,pathological damage,cerebral atrophy,liquefaction,and impairment were found,and Zea-Longa scores were significantly increased.The parental-generation rats were propagated at 3 months old,and offspring were obtained.No changes in the overall brain structures of these offspring rats were identified by magnetic resonance imaging.However,the escape latency was longer and the number of platform crossings was reduced among these offspring compared with normal rats.These results indicated that the offspring of hypoxic-ischemic encephalopathy model rats displayed cognitive impairments in learning and memory.This study was approved by the Animal Care&Welfare Committee of Kunming Medical University,China in 2018(approval No.kmmu2019072).
基金supported by the National Natural Science Foundation of China,No.81171239Frontier Research Project of Central South University in China,No.2177-721500065the Graduate Degree Thesis Innovation Foundation of Central South University in China
文摘This study aimed to investigate changes in secretory pathway Ca2＋-ATPase 2 expression following cerebral ischemia/reperfusion injury, and to define the role of Ca2＋-ATPases in oxidative stress. A rat model of cerebral ischemia/reperfusion injury was established using the unilateral middle cerebral artery occlusion method. Immunohistochemistry and reverse transcription-PCR assay results showed that compared with the control group, the expression of secretory pathway Ca2＋-ATPase 2 protein and mRNA in the cerebral cortex and hippocampus of male rats did not significantly change during the ischemic period. However, secretory pathway Ca2＋-ATPase 2 protein and mRNA expression reduced gradually at 1, 3, and 24 hours during the reperfusion period. Our experimental findings indicate that levels of secretory pathway Ca2＋-ATPase 2 protein and mRNA expression in brain tissue change in response to cerebral ischemia/reperfusion injury.
基金Supported by: the Foundation Program of Shandong Heatth Department, No. 2001CAICKAF
文摘BACKGROUND： Previous studies of cerebral ischemia have used young animals, with an ischemic time greater than 5 minutes （safe time limit）. Despite an increased understanding of neuronal apoptosis, it remains uncertain whether brief cerebral ischemic events of 5 minutes or less damage brain tissue in elderly rodents. OBJECTIVE： To investigate the effects of transient cerebral ischemia （5 minutes）/reperfusion injury on brain cortical and hippocampal edema, aquaporin-4 （AQP-4） expression, and neuronal apoptosis in aged rats, and to compare ischemic sensitivity between cortex and hippocampus. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Institute of Cerebrovascular Disease, Qingdao University Medical School from April 2008 to March 2009. MATERIALS： Rabbit anti-AQP-4 polyclonal antibody, TUNEL kit, and SABC immunohistochemistry kit were purchased from Wuhan Boster Bioengineering, China. METHODS： A total of 160 healthy, male, aged 19-21 months, Wistar rats were randomly assigned to 4 groups： sham-surgery, and ischemia 1-, 3-, and 5-minute groups, with 40 rats in each group. The global cerebral ischemia model was established using the Pusinelli four-vessel occlusion, and the three cerebral ischemia groups were subdivided into reperfusion 12-hour, 1-, 2-, 3-, and 7-day subgroups, with 8 rats in each subgroup. The sham-surgery group was subjected to exposure of the first cervical bilateral alar foramina and bilateral common carotid arteries. MAIN OUTCOME MEASURES： The dry-wet weight assay was used to measure brain water content and histopathology of the cortex and hippocampus was observed following hematoxylin-eosin staining. In addition, cortical and hippocampal AQP-4 expression was detected by streptavidin-biotin complex immunohistochemistry, and neuronal apoptosis was detected by the TUNEL method. RESULTS： There was no significant difference in brain water content or AQP-4 expression in the cortex and hippocampus between ischemia 1- and 3-minute groups and the sham-surgery group or brain water content or AQP-4 expression in the cortex between ischemia 5-minute group and sham-surgery group （P 〉 0.05）. However, brain water content and AQP-4 expression in the hippocampus after 5 minutes of cerebral ischemia were significantly increased compared with the sham-surgery group （P 〈 0.05 or P 〈 0.01）. Several TUNEL-positive cells were observed in the cortex and hippocampus of the sham-surgery group and ischemia 1-minute group, as well as in the cortex of the ischemia 3-minute group. In addition, the number of apoptotic neurons in the hippocampus of ischemia 3-minute group and in the cortex and hippocampus of ischemia 5-minute group was significantly increased （P 〈 0.05 or P 〈 0.01 ）. Neuronal apoptosis was increased after 12 hours of ischemia/reperfusion, and it reached a peak by 2 days （P 〈 0.01）. CONCLUSION： Transient cerebral ischemia （5 minutes） resulted in increased hippocampal edema, AQP-4 expression, and neuronal apoptosis. Moreover, cerebral ischemia had a greater effect on neuronal apoptosis than brain edema or AQP-4 expression, and the hippocampus was more sensitive than the cortex.
基金supported by Health and Medical Research Fund,the Food and Health Bureau,The Government of the Hong Kong Special Administrative Region(03142256)General Research Fund,Hong Kong Research Grants Council(GRF#HKU773613M)+1 种基金Seed Funding Programme for Basic Research(201811159123,201910159191)The University of Hong Kong(all to ACYL)。
文摘Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage.The mechanisms underlying exacerbated hemorrhage are not fully understood.This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy.The results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+mice.This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion.This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEGF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEGF up-regulation,resulting in rapid vessel disintegration in diabetic stroke.Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions.In conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation.Thus,suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window.Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong[CULATR 3834-15(approval date January 5,2016);3977-16(approval date April 13,2016);and 4666-18(approval date March 29,2018)].
文摘Objective： To determine whether AQP4 expression is associated with lactate （Lac） and Nacetyl aspartate （NAA） and with apparent diffusion coefficient （ADC） abnormality after rat cerebral ischemia. Methods： The time courses of ADC and lactate and NAA assessed by proton magnetic resonance spectroscopy （^1HMRS） were investigated at the time point of 6 h, and 1, 3, 7 d after rat cerebral ischernia induced by middle cerebral artery occlusion. Expression of AQP4 mRNA and protein were measured using RT-PCR and Western blot analysis respectively. Results： Significant reductions of NAA concentration and increases of lactate concentration were found after rat cerebral ischemia. The expressions of AQP4 mRNA t and protein were increased at 6 h, and reached the peak at 1-3 d, then began to decrease at 7 d after rat cerebral ischemia. The expression of AQP4 was significantly correlated with NAA （rRT = -0. 856, rw = -0. 927, P〈0.01）, and with lactate （rw=0. 473, rRT=0. 413, P〈0.05）, and with ADC values during the period of 1-7d after rat cerebralischemia （rw=0.984, rRT=0.925, P〈0.05）. In addition, correlations between Lac and the ADC values（r=-0. 677, P〈0.05）and between NAA and ADC values during the period of 1-7 d after rat cerebralischemia （r=0.909, P（0.05） were also observed. Conclusion： The data suggest that AQP4 is involved in the transport of water when brain edema is formed and cell membrane integrity is lost.
