Development of a new cerebral ischemia reperfusion model of Mongolian gerbils and standardized evaluation system

Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.

Neuroprotective effects of meloxicam on transient brain ischemia in rats:the two faces of anti-inflammatory treatments

The inflammato ry response plays an important role in neuroprotection and regeneration after ischemic insult.The use of non-ste roidal anti-inflammatory drugs has been a matter of debate as to whether they have beneficial or detrimental effects.In this context,the effects of the anti-inflammatory agent meloxicam have been scarcely documented after stro ke,but its ability to inhibit both cyclooxygenase isoforms(1 and 2) could be a promising strategy to modulate postischemic inflammation.This study analyzed the effect of meloxicam in a transient focal cerebral ischemia model in rats,measuring its neuroprotective effect after 48 hours and 7 days of reperfusion and the effects of the treatment on the glial scar and regenerative events such as the generation of new progenitors in the subventricular zone and axonal sprouting at the edge of the damaged area.We show that meloxicam’s neuroprotective effects remained after 7 days of reperfusion even if its administration was restricted to the two first days after ischemia.Moreover,meloxicam treatment modulated glial scar reactivity,which matched with an increase in axonal sprouting.However,this treatment decreased the formation of neuronal progenitor cells.This study discusses the dual role of anti-inflammatory treatments after stro ke and encourages the careful analysis of both the neuroprotective and the regenerative effects in preclinical studies.

Expression of neurocan mRNA and ultrastructure of brain tissue after cerebral ischemia and reperfusion in stroke-prone renovascular hypertensive rats treated by electroacupuncture

We established a stroke-prone renovascular hypertensive rat model by bilateral constriction of the renal artery with sliver loop clips. After ten weeks, middle cerebral artery occlusion was induced for 2 hours. The rats then received electro-acupuncture at Baihui （DU 20） and Dazhui （DU 14） after onset of ischemia for 30 days. In situ hybridization study showed that electroacupuncture significantly reduced the number of neurocan mRNA-positive cells in the ischemic penumbra and hippocampal tissues of rats. Electron microscopy results demonstrated that the structure of neurons and blood vessels in the ischemic tissues were restored with electroacupuncture. Overall, these data suggest that electroacupuncture may protect neurons against ischemic reperfusion injury in stroke-prone renovascular hypertensive rats, which may be regulated by downregulation of expression of nerve inhibitory factor neurocan mRNA.

Effects of “Nourishing Liver and Kidney” Acupuncture Therapy on Expression of Brain Derived Neurotrophic Factor and Synaptophysin after Cerebral Ischemia Reperfusion in Rats

The aim of the present study was to investigate the effect of ＂nourishing liver and kidney＂ acupuncture therapy on motor and cognitive deficits,and the underlying mechanism following cerebral ischemia-reperfusion（I/R） via increasing the expression of brain derived neurotrophic factor（BDNF） and synaptophysin（SYN） in the hippocampus.Healthy adult male SD rats were randomly divided into sham operation group（n=51）,model group（n=51）,acupuncture group（n=51） and acupuncture control group（n=51）.The middle cerebral I/R model was established.Acupunctures were performed in the acupuncture group and acupuncture control group at acupoints of Taixi（K103）,Taichong（ST09） of both sides,for 30 min once daily every morning.The animals in the sham operation group and model group were conventionally fed in the cage,without any intervention therapy.The rats of each group were assessed with modified neurological severity scores（m NSS）.The expression of BDNF and SYN in the hippocampus was detected by immunohistochemical SP method and the synaptic structure in hippocampus area was assessed morphologically and quantitatively at the 3rd,7th and 14 th day.The Morris water Maze（MWM） test was used to evaluate the rats＇ learning and memory abilities on the 15 th day after acupuncture.The animals in the acupuncture control group and sham operation group presented no neurological deficit.In the acupuncture group,the nerve functional recovery was significantly better than that in the model group at the 7th and 14 th day after modeling.The average MWM escape latency in the acupuncture group was shorter than that in the model group at the 3rd,4th and 5th day.The number of crossings of the platform quadrant in the acupuncture group was significantly more than that in the model group.At the each time point,the expression levels of BDNF and SYN in the hippocampal regions increased significantly in the model group as compared with the sham operation group and the acupuncture control group.In the acupuncture group,the expression levels of BDNF at the 7th and 14 th day increased more significantly than those in the model group.In the acupuncture group,the expression levels of SYN at the each time point increased more significantly than those in the model group.The post-synaptic density（PSD） was significantly increased and the synapse cleft width was narrowed in the acupuncture group as compared with other groups.The synaptic curvatures were improved obviously in the acupuncture group in contrast to the model group.It was concluded that the ＂nourishing liver and kidney＂ acupuncture therapy has positive effects on behavioral recovery,as well as learning and memory abilities,probably by promoting the expression of BDNF and SYN,and synaptic structure reconstruction in the ipsilateral hippocampus after I/R in rats.The ＂nourishing liver and kidney＂ acupuncture therapy can promote the functional recovery in rats after cerebral ischemia injury.

Expression of netrin-1 and its receptors, deleted in colorectal cancer and uncoordinated locomotion-5 homolog B, in rat brain following focal cerebral ischemia reperfusion injury

Netrin-1 is currently one of the most highly studied axon guidance factors. Netrin-1 is widely expressed in the embryonic central nervous system, and together with the deleted in colorectal cancer and uncoordinated locomotion-5 homolog B receptors, netrin-1 plays a guiding role in the construction of neural conduction pathways and the directional migration of neuronal cells. In this study, we established a rat middle cerebral artery ischemia reperfusion model using the intraluminal thread technique. Immunofluorescence microscopy showed that the expression of netrin-1 and deleted in colorectal cancer in the ischemic penumbra was upregulated at 1 day after reperfusion, reached a peak at 14 days, and decreased at 21 days. There was no obvious change in the expression of uncoordinated locomotion-5 homolog B during this time period. Double immunofluorescence labeling revealed that netrin-1 was expressed in neuronal cells and around small vessels, but not in astrocytes and microglia, while deleted in colorectal cancer was localized in the cell membranes and protrusions of neurons and astrocytes. Our experimental findings indicate that netrin-1 may be involved in post-ischemic repair and neuronal protection via deleted in colorectal cancer receptors.

Gap junction communication involved in brain protection following focal ischemia and reperfusion in rats

BACKGROUND： Studies have suggested that gap junctions not only modulate the fate of the neocortex, but are also involved in maintaining homeostasis in the mature brain. However, the neuroprotective effects of gap junction communication following brain ischemic injury remain poorly understood. OBJECTIVE： To investigate the neuroprotective effects and possible mechanisms of gap junction communication following focal ischemia and reperfusion. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the School of Basic Medical Sciences of Lanzhou University between June 2007 and May 2008. MATERIALS： Rabbit polyclonal anti-connexin 43 （Cx43） and gap junction blocking agent octanol were purchased from Sigma, USA; mouse monoclonal anti-rat glial fibrillary acidic protein （GFAP） was provided by Santa Cruz, USA; mouse monoclonal anti-rat CD11 b was produced by Abcam, England. METHODS： A total of 52 adult, male, Sprague Dawley rats were randomly assigned to three groups： sham-operated （n = 12）, vehicle control （n = 20）, and octanol-treated （n = 20）. Brain ischemia and reperfusion were induced by transient middle cerebral artery occlusion （MCAO） in vehicle control and octanol-treated groups, while no MCAO was administered to the sham-operated group. In the octanol-treated group, 5 mmol/kg octanol was dissolved in dimethyl sulfoxide （0.005% v/v） and was intraperitoneally injected 30 minutes prior to ischemic onset. Sham-operated and vehicle groups received equivalent volumes of dimethyl sulfoxide. MAIN OUTCOME MEASURES： Infarct volumes in ipsilateral striatum after MCAO were measured using cresyl violet dye; GFAP, CD11 b, and Cx43 expression in the ipsilateral striatum following MCAO were detected by immunohistochemistry; Western blot analysis was employed to determine Cx43 and GFAP expression. RESULTS： At 1 and 3 days following MCAO and reperfusion, ipsilateral striatum infarct volumes in the octanol group were significantly greater than in the vehicle group （P 〈 0.05）. There was no infarction in the sham-operated group. Cx43 and GFAP expression in the ipsilateral striatum of the octanol group was remarkably decreased compared with the vehicle group （P 〈 0.05）, and expression in the sham-operated group was less than in the other two groups （P 〈 0.05）. In the octanol-treated group, CD11 b expression was significantly increased compared with the vehicle group （P 〈 0.05）, and there were less CD11 b-immunoreactive cells in the sham-operated group compared with the other two groups （P 〈 0.05）. CONCLUSION： The pretreatment of blocking gap junction aggravated brain injury following MCAO. These results were possibly due to reduced astrocyte proliferation and activation, as well as reduced inflammatory response via activated microglia.

Upregulated expression of S100A8 in mice brain after focal cerebral ischemia reperfusion

BACKGROUND:Recent studies have showed that S100A8 has been implicated in the pathobiology of inflammatory disorders,and that cerebral ischemia reperfusion(l/R) rapidly activates inflammation responses via Toll-like receptor 4(TLR4).This study aimed to explore the expression of S100A8 and the relationship between S100A8 and TLR4 in focal cerebral ischemia reperfusion injury.METHODS:C3H/HeJ mice(n=30) and C3H/HeN mice(n=30) were divided randomly into a C3H/HeJ model group(n=18),a C3H/HeJ control group(n=12),a C3H/HeN model group(n=18),and a C3H/HeN control group(n=12).Middle cerebral artery l/R model in mice was produced using a thread embolism method.The brains of the mice were collected after ischemia for 1 hour and reperfusion for 12 hours.Stroke outcome was evaluated by determination of infarct volume and assessment of neurological impairment scores.Brain injury after cerebral l/R was observed by an optical microscope after TTC and HE dyeing.The immunofluorescence technique and real time PCR were used to test the expression level of S100A8 in brain damage.RESULTS:Compared with C3H/HeN mice,TLR4-deficient mice(C3H/HeJ) had lower infarct volumes and better outcomes in neurological tests.The levels of S100A8 increased sharply in the brains of mice after l/R injury.In addition,mice that lacked TLR4(C3H/HeJ) had lower expression of l/R-induced S100A8 than C3H/HeN mice in the model group,indicating that a close relationship might exist between the levels of S100A8 and TLR4.CONCLUSION:S100A8 interaction with TLR4 might be involved in brain damage and in inflammation triggered by l/R injury.

Relationship of gelatinases-tight junction proteins and blood-brain barrier permeability in the early stage of cerebral ischemia and reperfusion

Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[（2R）-2-（hydroxamidocarbonylmethyl）-4-methylpenthanoyl]-L- tryptophan methylamide （GM6001） showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier （tight junction proteins） is of importance.

Expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in brain tissue of diabetic rats with ischemia reperfusion

Objective: To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. Methods: A total of 60 male Wistar rats were randomly divided into the normal group, sham group, diabetic cerebral infarction group and single cerebral infarction group according to the random number table, with 15 rats in each group. The high sucrose diet and intraperitoneal injection of streptozotocin were performed for the modeling of diabetic rats, while the thread-occlusion method was employed to build the model of cerebral ischemia reperfusion. The immunohistochemical staining was performed to detect the expression of angiostatin, vascular endothelial growth factor(VEGF) and matrix metalloproteinase-9(MMP-9) in the brain tissue. Results: The expression of angiostatin after the reperfusion in the brain tissue of rats in the single cerebral infarction group and diabetic cerebral infarction group was increased 6 h after the reperfusion, reached to the peak on 1 d and then decreased gradually. The expression of angiostatin in the diabetic cerebral infarction group 6 h, 1 d, 3 d and 7 d after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). VEGF began to be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak at 6 h and then decreased gradually. The expression of VEGF in the diabetic cerebral infarction group at each time point after the reperfusion was significantly lower than that in the single cerebral infarction group(P<0.05). MMP-9 began to be be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak on 1 d and then decreased gradually. The expression of MMP-9 in the diabetic cerebral infarction group at each time point after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). Conclusions: The high glucose environment in which the diabetic cerebral infarction is occurred is to induce the formation of MMP-9 at first and then activate and increase the expression of angiostatin. Afterwards, the expression of VEGF is inhibited, resulting in the poor angiogenesis after cerebral infarction, which thus makes the injury of brain tissue after cerebral infarction even worse than the non-diabetes mellitus.

Effect of compound preparation Tongqiao Jiannao capsules on neural cell apoptosis and Bcl-2 and Bax protein levels in a rat model of brain ischemia/reperfusion injury

BACKGROUND：Pharmacological studies have demonstrated that compound preparation Tongqiao Jiannao capsules composed of Zexie, Baizhu, Honghua, Danshen, and Shexiang can supplement qi, activate blood circulation, relieve blood stasis, induce resuscitation for alleviating pain, relieve pain, and dilate blood vessels. OBJECTIVE： To observe the effects of Tongqiao Jiannao capsules on the levels of the anti-apoptotic protein Bcl-2 and the proapoptotic protein Bax, and verify the mechanism of action. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment, performed in the Laboratory of Biochemistry and Molecular Biology, Shanxi Medical University between June 2001 and December 2002. MATERIALS： The right middle cerebral arteries of 24 healthy adult Sprague Dawley rats were occluded by the suture method. The primary Chinese herbal medicinal ingredients of Tongqiao Jiannao capsules are Zexie, Baizhu, Honghua, Danshen, and Shexiang, which were purchased from Shanxi Provincial Medicinal Material Company, China, and prepared into condensed granules in the Room for Chinese Herbal Medicine Preparation, Second Hospital, Shanxi Medical University. Bcl-2 and Bax immunohistochemical staining kits, a 3,3-diaminobenzidine（DAB） kit, and an in situ apoptosis detection kit were purchased from Wuhan Boster Bioengineering Co., Ltd., China. METHODS： Twenty-four rats were randomly and evenly divided into three groups： （1） sham-operated rats in which sutures were inserted and immediately pulled out; （2） Tongqiao Jiannao capsule-treated rats that were intragastrically administered 6.5 g/kg/d Tongqiao Jiannao capsule preparation for seven successive days prior to middle cerebral artery occlusion （MCAO）; and （3） MCAO rats without any other treatments. MAIN OUTCOME MEASURES： The levels of neural cell apoptosis and Bcl-2 and Bax proteins at 24 hours post-surgery. RESULTS： In the MCAO group, the numbers of apoptotic cells and Bax-positive cells were significantly increased, while the numbers of Bcl-2-positive cells were slightly decreased compared with the sham-operated group. Bcl-2- and Bax-positive cells and apoptotic cells were primarily distributed in the ischemic penumbra. In the Tongqiao Jiannao capsule-treated group, neuronal apoptosis was inhibited, and the number of Bcl-2-positive cells was significantly increased （P 〈 0.01）, while the number of Bax-positive cells was significantly decreased （P 〈 0.01）, compared with the MCAO group. CONCLUSION： Tongqiao Jiannao capsules elevated Bcl-2 expression, lowered Bax expression, and inhibited cellular apoptosis during the process of cerebral ischemia/reperfusion injury.

Effects of RSM and astragus on expression of Fos and Jun proteins in rat brains after cerebral ischemia and reperfusion

AIM: To investigate the expression of Fos and Jun proteins in rat brains after focal cerebral ischemia followed by reperfusion and effects of RSM and astragus.METHODS: 30 SD adult male rats were divided into 5 groups at random .Group A:sham operated group;Group B:model group;Group C:treated with RSM;Group D:treated with astragus;Group E:treated with RSM and astragus.The immunohistochemistry and medical image processing system(MIPS)were used to measure the numbers and mean grey levels of Fos and Jun protein positive cells in rat cerebral cortex of 5 groups. RESULTS: (1) In cerebral cortex of group B ,C ,D ,E,the numbers of Fos and Jun positive cells were more than those in group A and mean grey levels of Fos and Jun positive cells were lower than those in group A(P< 0.01);(2) In cerebral cortex of ischemic sides in group C,D,E,the numbers of Fos and Jun positive cells were less than those in group B and mean grey levels of Fos and Jun positive cells were higher than those in group B(P< 0.01) ;(3) Group E had more significant effects than group C or group D (P< 0.01). CONCLUSION: The expression of Fos protein and Jun protein in model group increased significantly,compared with sham operated group;RSM ,astragus ,RSM and astragus all could inhibit partly the expression of Fos protein and Jun protein after cerebral ischemia and reperfusion;Prescription of RSM and astragus had stronger inhibiting effects than RSM or astragus.It may be one of mechanisms that ischemic stoke is treated by reinforcing Qi and activating blood circulation therapy in TCM clinic.

Effect of propofol pretreatment on apoptosis in rat brain cortex after focal cerebral ischemia and reperfusion

The present study aimed to observe cortical expression of Bcl-2 and Bax,cysteine-dependent aspartate directed proteases-3 activity and apoptotic cell death in a rat model of middle cerebral artery occlusion pretreated with propofol.Results showed that,propofol pretreatment significantly reduced oxidative stress levels and attenuated neuronal apoptosis in the cortex of rats.Propofol pretreatment upregulated Bcl-2 expression,and downregulated Bax expression and cysteine-dependent aspartate directed proteases-3 activity.These findings indicate that propofol pretreatment inhibits cell apoptosis during focal cerebral ischemia/reperfusion injury.This neuroprotective effect is most likely achieved through the Bcl-2/Bax/cysteine-dependent aspartate directed proteases-3 pathway.

Moderate alcohol preconditioning activates BKCa channels to protect brain damage-induced by cerebral ischemia and reperfusion

OBJCETIVE Epidemiologic studies have demonstrated that consumption of moderate amounts of red wine is associated with significant reductions in incidences of cardiovascular and cerebrovascular diseases,which may be related to alcohol in red wine.Our previous study demonstrated that ethanol ingestion 24 h prior to induction of cerebral ischemic/reperfusion(I/R)reduced delayed neuronal death(DND).Our most recent results supported a role for big Ca2+-sensitive K+channel(BKCa channel)activation in the neuroprotective effects of ethanol preconditioning(Et OH-PC)in global cerebral I/R.Therefore,we hypothesis that moderate Et OH-PC activates BKCa channel to protect brain damage induced by focal cerebral I/R.This project will utilize focal cerebral I/R animal model to explore the function of BKCa channel in Et OH-PC protection in vivo levels by means of pharmacological intervention such as BKCa channel opene(rNS11021,NS)and blocke(rpaxilline,PX).The results will provide theoretical evidence for neuroprotective effect of moderate alcohol preconditioning against ischemic stroke,and the conclusion will also bring to a concept that extrinsic moderate ethanol preconditioning may activate intrinsic protective mechanism in the brain.METHODS The SD rat were randomly divided into the following six groups(n=10):sham,I/R,Et OH-PC+I/R,NS11021-PC+I/R,paxilline+Et OH-PC+I/R,Paxilline+NS11021-PC+I/R.Both Et OH-PC and NS11021-PC(0.1mg·kg-1;ip)were induced 24 h before I/R.The volume of 95%ethanol to be instilled(inμL)was calculated as follows:〔body weight(g)×0.6〕+0.3.This volume of ethanol was mixed in 0.3 m L of sterile distilled water just before administration to the animals by gavage.The Paxilline(2.5 mg·kg-1;ip)was administered 10min beforeEt OH-PC and NS11021-PC.The right middle cerebral artery occlusion(MCAO)was produced by inversion of a 4-0-nylon filament.The filament was withdrawn 2 h after onset of MCAO and then reperfused.Neurological deficits and infarct volume were measured 24 h after I/R.Another 36 rats were randomly divided into 6 groups as above,6 in each group.DWI were performed 2h after ischemic and T2WI MRI were performed 24 h after I/R to observe the infarct volume of brain and the penumbra volume of brain in each group.Then rats were killed and detected the apoptotic cell death and degeneration of neurons.RESULTS Compared to I/R group,the neurological score(P<0.01),the infarct volume of brain(P<0.01),the infarct volume of ischemic penumbra(P<0.01),the percentage of apoptotic cell death(P<0.01)and the percentage of degenerative neurons(P<0.01)were significantly decreased after ethanol preconditioning,while these changes were reversed by paxilline(P<0.05);compared to I/R group,the neurological score(P<0.01),the infarct volume of brain(P<0.01),the infarct volume of ischemic penumbra(P<0.01),the percentage of apoptotic cell death(P<0.01)and the percentage of degenerative neurons(P<0.01)were significantly decreased after NS11021 preconditioning,while these changes were reversed by paxilline(P<0.05).CONCLUSION Our results show that moderate alcohol preconditioning activates BKCa channels to protect brain damage induced by focal cerebral I/R.

Effects of Panax Notoginseng Saponin on the Expression of Vascular Endothelial Growth Factor after the Brain Ischemia-reperfusion Injury in Rats

Objective： To observe effects of Panax Notoginseng Saponin （PSN） on the expression of Vascular Endothelial Growth Factor （VEGF） after the brain ischemia-reperfusion injury in rats. Methods： 48 SD rats had been randomly divided into 4 groups： the sham operation group, the model group, Panax Notoginseng Saponin （PNS） group and Nimodipine group （n=12） . The rats had been treated with PNS, and 7 days later the rat focal cerebral ischemia-reperfusion models had been pre- pared. Neurobehavioral scores （NBS） had been evaluated in each group, TTC staining observed; the immunohistochemistry was used to observe VEGF and mRNA expressions. Results： PNS could not only improve significantly neurobehavioral scores and decrease dramatically cerebral infarct volume, but also increase remarkably VEGF and mRNA expression levels. Conclusion： The PNS is beneficial for rehabilitation after cerebral ischemia reperfusion injury via effectively up-regulating the injured cor- tical VEGF mRNA expression concentrations, which promotes vascular reborn in the ischemic region.

Synthesis, characterization and in vivo evaluation of honokiol bisphosphate prodrugs protects against rats’ brain ischemia-reperfusion injury

Honokiol(HK)usage is greatly restricted by its poor aqueous solubility and limited oral bioavailability.We synthesized and characterized a novel phosphate prodrug of honokiol(HKP)for in vitro and in vivo use.HKP greatly enhanced the aqueous solubility of HK(127.54±15.53 mg/ml)and the stability in buffer solution was sufficient for intravenous administration.The enzymatic hydrolysis of HKP to HK was extremely rapid in vitro(T 1/2=8.9±2.11 s).Pharmacokinetics studies demonstrated that after intravenous administration of HKP(32 mg/kg),HKP was converted rapidly to HK with a time to reach the maximum plasma concentration of^5 min.The prodrug HKP achieved an improved T 1/2(7.97±1.30 h)and terminal volume of distribution(26.02±6.04 ml/kg)compared with direct injection of the equimolar parent drug(0.66±0.01 h)and(2.90±0.342 ml/kg),respectively.Furthermore,oral administration of HKP showed rapid and improved absorption compared with the parent drug.HKP was confirmed to maintain the bioactivity of the parent drug for ameliorating ischemia-reperfusion injury by decreasing brain infarction and improving neurologic function.Taken together,HKP is a potentially useful aqueous-soluble prodrug with improved pharmacokinetic properties which may merit further development as a potential drug candidate.

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

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.

GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis in rats

Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion （I/R） injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/（kg.day）, 25 mg/（kg.day） or 50 mg/（kg.day） intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase （CSE） activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.

Transplantation of X-box-binding protein-1 gene-modified neural stem cells in the lateral ventricle of brain ischemia rats

X-box-binding protein-1 （XBP-1） is an essential transcription factor in endoplasmic reticulum stress In this study, XBP-1 gene-transfected neural stem cells （NSCs） were transplanted into lesion sites to ensure stability and persistent expression of XBP-1, resulting in the exertion of anti-apoptotic effects. Simultaneously, XBP-1 gene transfection promotes the survival and differentiation of transplanted NSCs. Results from this study demonstrated that survival, proliferation and differentiation of XBP-1 g^ne-modified NSCs were enhanced when compared to unmodified NSCs at 28 days post-transplantation （P 〈 0.05）. A diminished number of apoptotic neural cells increased Bcl-2 expression and reduced Bax expression, and were observed in the ischemic region of the XBP-1-NSCs group （P 〈 0.05）. These results indicated that modification of the XBP-1 gene enhances the survival and migration of NSCs in vivo and decreases the occurrence of apoptosis.

Neuroprotective effects of rutaecarpine on cerebral ischemia reperfusion injury

Rutaecarpine, an active component of the traditional Chinese medicine Tetradium ruticarpum, has been shown to improve myocardial ischemia repeffusion injury. Because both cardiovascular and cerebrovascular diseases are forms of ischemic vascular disease, they are closely related. We hypothesized that rutaecarpine also has neuroprotective effects on cerebral ischemia reperfusion injury. A cerebral ischemia reperfusion model was established after 84, 252 and 504 pg/kg rutae- carpine were given to mice via intrapedtoneal injection, daily for 7 days. Results of the step through test, 2,3,5-triphenyl tetrazolium chloride dyeing and oxidative stress indicators showed that rutae- carpine could improve learning and memory ability, neurological symptoms and reduce infarction volume and cerebral water content in mice with cerebral ischemia reperfusion injury. Rutaecarpine could significantly decrease the malondialdehyde content and increase the activities of superoxide dismutase and glutathione peroxidase in mouse brain. Therefore, rutaecarpine could improve neu- rological function following injury induced by cerebral ischemia reperfusion, and the mechanism of this improvement may be associated with oxidative stress. These results verify that rutaecarpine has neuroprotective effects on cerebral ischemia reperfusion in mice.

Microvessel changes in the gerbil hippocampus after cerebral ischemia and reperfusion by Buyang Huanwu decoction pretreatment

Buyang Huanwu decoction （BYHWD） is a classic recipe for the prevention and treatment of ischemic cerebrovascular disease. Gerbils were pretreated with BYHWD, and then subjected to cerebral ischemia and reperfusion. Microvascular changes were determined with laser Doppler monitoring, tannic acid-ferric chloride mordant, and electron microscopy. Results showed that BYHWD pretreatment could enhance the function of hippocampal microvessels, prevent injury, and increase microvasular density and microvasular area density. Thus, these results suggest that BYHWD pretreatment could prevent microvascular occlusion, enhance the capacity of microvascular reperfusion, increase cerebral blood flow, and inhibit neuronal damage, and may be an effective therapy against brain ischemic injury.