Recurrent Transient Ischemic Attacks Revealing Cerebral Amyloid Angiopathy: A Comprehensive Case

This case report investigates the manifestation of cerebral amyloid angiopathy (CAA) through recurrent Transient Ischemic Attacks (TIAs) in an 82-year-old patient. Despite initial diagnostic complexities, cerebral angiography-MRI revealed features indicative of CAA. Symptomatic treatment resulted in improvement, but the patient later developed a fatal hematoma. The discussion navigates the intricate therapeutic landscape of repetitive TIAs in the elderly with cardiovascular risk factors, emphasizing the pivotal role of cerebral MRI and meticulous bleeding risk management. The conclusion stresses the importance of incorporating SWI sequences, specifically when suspecting a cardioembolic TIA, as a diagnostic measure to explore and exclude CAA in the differential diagnosis. This case report provides valuable insights into these challenges, highlighting the need to consider CAA in relevant cases.

Transient ischemic attack induced by pulmonary arteriovenous fistula in a child:A case report

BACKGROUND Cerebral ischemic stroke is attributed to paradoxical cerebral embolism.Pulmonary arteriovenous fistula(PAVF)is a rare potential cause of cerebral ischemic stroke,and cerebral ischemic stroke induced by PAVF in children is rare.CASE SUMMARY We report a case of right PAVF that presented as a transient ischemic attack(TIA)in a 13-year-old boy.The patient underwent embolization therapy and remained clinically stable for 2 years after treatment.CONCLUSION TIA induced by PAVF in children is rare,lacks typical clinical manifestations,and should not be ignored.

Pretreated Oenan the Javanica extract increases anti-inflammatory cytokines, attenuates gliosis, and protects hippocampal neurons following transient global cerebral ischemia in gerbils

Recently,we have reported that Oenanthe javanica extract(OJE)displays strong neuroprotective effect against ischemic damage after transient global cerebral ischemia.However,neuroprotective mechanisms of OJE have not been fully identified.Thus,this study investigated the neuroprotection of OJE in the hippocampal CA1 area and its anti-inflammatory activity in gerbils subjected to 5 minutes of transient global cerebral ischemia.We treated the animals by intragastrical injection of OJE(100 and 200 mg/kg)once daily for 1 week prior to transient global cerebral ischemia.Neuroprotection of OJE was observed by immunohistochemistry for neuronal nuclear antigen and histofluorescence staining for Fluoro-Jade B.Immunohistochemistry of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 was done for astrocytosis and microgliosis,respectively.To investigate the neuroprotective mechanisms of OJE,we performed immunohistochemistry of tumor necrosis factor-alpha and interleukin-2 for pro-inflammatory function and interleukin-4 and interleukin-13 for anti-inflammatory function.When we treated the animals by intragastrical administration of 200 mg/kg of OJE,hippocampal CA1 pyramidal neurons were protected from transient global cerebral ischemia and cerebral ischemia-induced gliosis was inhibited in the ischemic hippocampal CA1 area.We also found that interleukin-4 and-13 immunoreactivities were significantly increased in pyramidal neurons of the ischemic CA1 area after OJE pretreatment,and the increased immunoreactivities were sustained in the CA1 pyramidal neurons after transient global cerebral ischemia.However,OJE pretreatment did not increase interleukin-2 and tumor necrosis factor-alpha immunoreactivities in the CA1 pyramidal neurons.Our findings suggest that pretreatment with OJE can protect neurons and attenuate gliosis from transient global cerebral ischemia via increasing expressions of interleukin-4 and-13.The experimental plan of this study was reviewed and approved by the Institutional Animal Care and Use Committee(IACUC)in Kangwon National University(approval No.KW-160802-1)on August 10,2016.

Characterization of astrocytes and microglial cells in the hippocampal CA1 region after transient focal cerebral ischemia in rats treated with Ilexonin A

Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the peri-infarct area after ischemia.However,the effects of ilexonin A on astrocytes and microglia in the infarct-free region of the hippocampal CA1 region remain unclear.Focal cerebral ischemia models were established by 2-hour occlusion of the middle cerebral artery in rats.Ilexonin A(20,40 or 80 mg/kg)was administered immediately after ischemia/reperfusion.The astrocyte marker glial fibrillary acidic protein,microglia marker Iba-1,neural stem cell marker nestin and inflammation markers were detected by immunohistochemistry and western blot assay.Expression levels of tumor necrosis factor-αand interleukin 1βwere determined by enzyme linked immunosorbent assay in the hippocampal CA1 tissue.Astrocytes were activated immediately in progressively increasing numbers from 1,3,to 7 days post-ischemia/reperfusion.The number of activated astrocytes further increased in the hippocampal CA1 region after treatment with ilexonin A.Microglial cells remained quiescent after ischemia/reperfusion,but became activated after treatment with ilexonin A.Ilexonin A enhanced nestin expression and reduced the expression of tumor necrosis factor-αand interleukin 1βin the hippocampus post-ischemia/reperfusion.The results of the present study suggest that ilexonin A has a neuroprotective effect in the hippocampus after ischemia/reperfusion,probably through regulating astrocytes and microglia activation,promoting neuronal stem cell proliferation and reducing the levels of pro-inflammatory factors.This study was approved by the Animal Ethics Committee of the Fujian Medical University Union Hospital,China.

Cerebral perfusion in corresponding blood supply areas of transient ischemic attack patients with intracranial stenosis Seven cases of diamox-perfusion verified by magnetic resonance-perfusion-weighted imaging

BACKGROUND： Due to collateral circulation and cerebrovascular reserve, arterial stenosis and reduced cerebral blood flow may not necessarily indicate impaired cerebral peffusion. Therefore, according to degree of stenosis and clinical symptoms, interventional surgery to relieve arterial stenosis in transient ischemic attack （TIA） patients with major intracranial stenosis is imprudent. Rather, cerebral perfusion and reserve capacity are direct indicators for the assessment of degree and presence of cerebral ischemia. OBJECTIVE： To evaluate cerebral perfusion and reserve in TIA patients with major intracranial stenosis or occlusion using magnetic resonance-perfusion-weighted imaging （MR-PWl） data prior to and following diamox administration. DESIGN, TIME AND SETTING： A self-comparative, neuroimaging observation was performed at the Neurological Department and Radiological Center of the First Affiliated Hospital of Jinan University between December 2007 and April 2009. PARTICIPANTS： Seven acute TIA patients, who were admitted to the Neurological Department of the First Affiliated Hospital of Jinan University between December 2007 and April 2009, were enrolled in the present study. Magnetic resonance imaging confirmed that no acute cerebral infarction happened, nor did bleeding exist. Magnetic resonance angiography, transcranial Doppler ultrasound, and/or digital subtraction angiography confirmed the presence of major intracranial arterial stenosis. Clinical symptoms corresponded to blood supplying regions of the arterial stenosis. METHODS： Baseline MR-PWI was performed on seven patients with intracranial stenosis or occlusion. Two grams of acetazolamide （diamox） were orally administered after 2 days. A second PWl was performed after 2 hours to compare cerebral perfusion parameters prior to and following diamox administration. MAIN OUTCOME MEASURES： PWI results of cerebral perfusion prior to and following diamox administration. RESULTS： The baseline PWl from five patients indicated decreased cerebral perfusion areas. Following oral administration of diamox, cerebral perfusion significantly decreased in those areas. Moreover, new areas of decreased cerebral perfusion were observed in two out of the five patients. In one patient, no significant decrease in cerebral perfusion was found. In another patient, baseline PWl indicated decreased cerebral perfusion in the left hemisphere. However, normal perfusion was observed in both cerebral lobes following diamox administration. CONCLUSION： TIA patients with intracranial stenosis, who are diagnosed by PWI and exhibited decreased cerebral perfusion and reserve, might require further treatment such as intervention by angioptasty.

Awareness intervention for Beijing neurologists regarding secondary prevention of cerebral infarction/transient ischemia Cross-sectional investigation

BACKGROUND： Stroke prevention guidelines should be made available application to aid in uniformity, timing, preciseness, and acceptance of disease. OBJECTIVE： To investigate the awareness of neurologists in some Beijing secondary prevention of cerebral infarction/transient ischemia. DESIGN： Cross-sectional study. to neurologists for clinical hospitals of intervention in SETTING： Beijing Tiantan Hospital, Beijing Anzhen Hospital, General Hospital of Beijing Military Area, Command of Chinese PLA, Beijing Chuiyangliu Hospital, Beijing 6^th Hospital, Beijing Hepingli Hospital, and Beijing Daxing District Hospital. PARTICIPANTS： A total of 28 （associate） chief physicians, 58 attending physicians, and 54 resident physicians who engaged in clinical treatment of cerebrovascular diseases were selected from 8 hospitals in Beijing from March to April 2007. All physicians provided informed consent. METHODS： Self-made closed questionnaires were provided for data collection, consisting of 16 questions that were single choice or multiple choice. Specifically, questions 1-7 focused on awareness of blood pressure regulation in different patients and first choice of decompression drug; questions 8-12 focused on awareness of lipid regulation; and questions 13-16 focused on awareness of anti-blood platelet drugs applied in secondary prevention. The scores ranged from 0-100 points, and each question was worth 6.25 points. The scores positively correlated with the awareness rate. To test leveling real-time, the survey lasted for a maximum of 20 minutes. One questionnaire was independently finished by each subject in the survey. MAIN OUTCOME MEASURES： Awareness intervention among neurologists during secondary prevention of cerebral infarction/transient ischemia and questionnaire scores. RESULTS： 140 subjects were included in the final analysis. ① The awareness rate among neurologists for intervention during secondary prevention of cerebral infarction/transient ischemia ranged from 0.7-57.9%, the scores ranged between 0-56 points, and the mean score was 26 points.② Scores of resident physicians were 0-56 points with a mean score of 26 points; attending physicians scored 6-50 points, with a mean score of 26 points; and chief physicians scored 6-50 points, with a mean score of 23 points. There were no significant differences among the various physicians （F = 0.771, t = 0.465, P 〉 0.05）. CONCLUSION： Awareness among neurologists of intervention during secondary prevention of cerebral infarction/transient ischemia is not ideal. However, there was no significant difference between professional titles.

Effect of restraint stress on depression-like behaviors in rats after transient focal cerebral ischemic injury

BACKGROUND： Restraint stress is a typical psychophysiological stressor. Simulating the early passion and difficulty in walking of patients after attack of stroke meets onset features.OBJECTIVE： To evaluate the effect of restraint stress on depression-like behaviors in rats after transient focal cerebral ischemic injury, and to investigate the feasibility for its being as modeling method of depression model after stroke.DESIGN： A randomized controlled animal experiment.SETTING： Department of Clinical Medicine, Faculty of Aerospace Medicine of the Fourth Military Medical University of Chinese PLA.MATERIALS： Forty-eight male Sprague-Dawley rats, weighing 240 - 270 g, provided by the Experimental Animal Center of the Fourth Military Medical University of Chinese PLA were used in the current study.METHODS： The experiments were carried out in the Faculty of Aerospace Medicine of the Fourth Military Medical University of Chinese PLA between August 2005 and August 2006. ①Experiment intervention： The rats were randomized into middle cerebral artery occlusion-reperfusion （MCAO） ＋stress group, simple MCAO group, sham-operation ＋ stress group and simple sham-operation group, with 12 rats in each group.Rats in the first two groups were developed into cerebral ischemia/reperfusion models by suture-occluded method. Rats in the MCAO＋stress group were modeled and restraint stress scheme was performed. At week 5 after modeling, the rats were placed in self-made restraining tubes, 2 hours/time, once a day, for 2 successive weeks. The common carotid artery, external and internal carotid arteries of rats in the latter two groups were exposed. The stress way of sham-operation＋ stress group was the same as that of MCAO＋ stress group. ②The neurological status grading and motor performance evaluation （screen test, rota-rod test and balance beam test） were conducted in rats with simple sham-operation group and MCAO group before, 1st and 28^th days after modeling. Depression-like behavior test was performed in the rats of each group by sucrose preference test and open field test at the end of the experiment.MAIN OUTCOME MEASURES： Changes of depression-like behaviors of rats in each group.RESULTS： Forty-eight rats were involved in the experiment. Two rats with meningeal irritation sign were excluded from simple MCAO group, and one rat in the MCAO＋stress group died of some unclear causes during the experiments. The other 45 rats entered the stage of finial analysis. ① Depression-like behavior assessment results： The rats in the MCAO＋ stress group had a significantly decreased preference for sucrose solution, crossing and rearing scores, and increased immobility duration after the 14-day restraint stress,compared with those in other three groups （all P〈0.05）. ②The neurological status grading and motor performance evaluation： There were significant differences in the two indexes of rats in the simple MCAO group before, 1^st and 28^th days after modeling （P〈0.01）, while there was no significant difference before and 28^th days after modeling （P〉0.05）. There were no significant changes in sham-operation group at each time point （P〉0.05）.CONCLUSION： After being exerted restraint stress, the rats with transient focal ischemic injury may show obvious depression-like behaviors. Therefore, restraint stress can be used as a novel animal modeling method for further studying biological mechanism in central nervous system of post-stroke depression animals.

Pretreated quercetin protects gerbil hippocampal CA1 pyramidal neurons from transient cerebral ischemic injury by increasing the expression of antioxidant enzymes

Quercetin（QE; 3,5,7,3′,4′-pentahydroxyflavone）, a well-known flavonoid, has been shown to prevent against neurodegenerative disorders and ischemic insults. However, few studies are reported regarding the neuroprotective mechanisms of QE after ischemic insults. Therefore, in this study, we investigated the effects of QE on ischemic injury and the expression of antioxidant enzymes in the hippocampal CA1 region of gerbils subjected to 5 minutes of transient cerebral ischemia. QE was pre-treated once daily for 15 days before ischemia. Pretreatment with QE protected hippocampal CA1 pyramidal neurons from ischemic injury, which was confirmed by neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, pretreatment with QE significantly increased the expression levels of endogenous antioxidant enzymes Cu/Zn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in the hippocampal CA1 pyramidal neurons of animals with ischemic injury. These findings demonstrate that pretreated QE displayed strong neuroprotective effects against transient cerebral ischemia by increasing the expression of antioxidant enzymes.

Middle cerebral artery occlusion methods in rat versus mouse model of transient focal cerebral ischemic stroke

Experimental stroke research commonly employs focal cerebral ischemic rat models （Bederson et al., 1986a; Longa et al., 1989）. In human patients, ischemic stroke typically results from thrombotic or embolic occlusion of a major cerebral artery, usually the mid- dle cerebral artery （MCA）. Experimental focal cerebral ischemia models have been employed to mimic human stroke （Durukan and Tatlisumak, 2007）. Rodent models of focal cerebral ischemia that do not require craniotomy have been developed using intraluminal suture occlusion of the MCA （MCA occlusion, MCAO） （Rosamond et al., 2008）. Furthermore, mouse MCAO models have been wide- ly used and extended to genetic studies of cell death or recovery mechanisms （Liu and McCullough, 2011）. Genetically engineered mouse stroke models are particularly useful for evaluation of isch- emic pathophysiology and the design of new prophylactic, neuro- protective, and therapeutic agents and interventions （Armstead et al., 2010）. During the past two decades, MCAO surgical techniques have been developed that do not reveal surgical techniques for mouse MCAO model engineering. Therefore, we compared MCAO surgical methods in rats and mice.

Nerve growth factor downregulates c-jun mRNA and Caspase-3 in striate cortex of rats after transient global cerebral ischemia/reperfusion

BACKGROUND： Immediate early gene （lEG） c-jun is a sensitive marker for functional status of nerve cells. Caspase-3 is a cysteine protease, which is a critical regulator of apoptosis. The effect of exogenous nerve growth factor （NGF） on the expression of c-jun mRNA and Caspase-3 protein in striate cortex of rats with transient global cerebral ischemia/reperfusion （IR） is unclear. OBJECTIVE： To study the protective effect of exogenous NGF on the brain of rats with transient globa cerebral IR and its effecting pathway by observing the expression of c-jun mRNA and Caspase-3 protein. DESIGN： Randomized controlled animal trial SETTING： Department of Neural Anatomy, Institute of Brain, China Medical University MATERIALS：Eighteen healthy male SD rats of clean grade, aged 1 to 3 months, with body mass of 250 to 300 g, were involved in this study. NGF was provided by Dalian Svate Pharmaceutical Co.,Ltd. c-jun in situ hybridization detection kit, Caspase-3 antibody and SABC kit were purchased from Boster Biotechnology Co.. Ltd. METHODS： This trial was carried out in the Department of Neural Anatomy, Institute of Brain, China Medical University during September 2003 to April 2005. （1） Experimental animals were randomized into three groups with 6 in each： sham-operation group, IR group and NGF group.（2）After the rats were anesthetized, the bilateral common carotid arteries and right external carotid arteries of rats were bluntly dissected and bilateral common carotid arteries were clamped for 30 minutes with bulldog clamps. Reperfusion began after buldog clamps were removed. Normal saline of lmL and NGF （1×10^6 U/L） of 1 mL was injected into the common carotid artery of rats via right external carotid arteries in the IR group and NGF group respectively. The injection was conducted within 30 minutes, and then the right external carotid arteries were ligated. In the sham-operation group, occlusion of bilateral common carotid arteries and administration of drugs were omitted.GAll the rats were executed by decollation at 3 hours after modeling. The animals were fixed with phosphate buffer solution （PBS, 0.1 mol/L） containing 40 g/L polyformaldehyde, their brains were quickly removed. The coronal section tissue mass containing striate cortex about 3 mm before line between two ears was taken and made into successive frozen sections.（4）The expression of c-jun mRNA and Caspase-3 protein in striate cortex of global cerebral ischemia rats were detected with in situ hybridization, immunohistochemistry and microscope image analysis. （5）t test was used for comparing the difference of the measurement data. MAIN OUTCOME MEASURES：Comparison of the expression of lEG c-jun mRNA and Caspase-3 protein in striate cortex of brain of rats in each group. RESULTS：All the 18 SD rats were involved in the analysis of results. The c-jun mRNA and Caspase-3 protein positive reaction cells were found brown yellow in the striate cortex of rats, and most of them were in lamellas Ⅱ and Ⅲ, mainly presenting round or oval. The expression of c-jun mRNA and Caspase-3 protein in sham-operation group was weak or negative. The average gray value of c-jun mRNA and Caspase-3 protein in the IR group was significantly lower than that in the sham-operation group （49.52±4.13 vs. 95.48± 5.28; 74.73±4.29 vs. 162.38±9.16,P 〈 0.01）. The average gray value of c-jun mRNA and Caspase-3 protein in the NGF group was significantly higher than that in the IR group （63.96±4.25 vs.49.52±4.13; 83.98± 4.13 vs. 74.73±4.29, P〈 0.05）. CONCLUSION： NGF can protect ischemic neurons by down-regulating the expression of c-jun mRNA and Caspase-3 protein in striate cortex of global cerebral ischemia rats.

Aggregation Patterns of Proteasome in Injured Neurons Induced by Transient Cerebral Ischemia

Proteasome activity reduction is an important pathological phenomenon, resulting in proteins aggregation and neuronal death in the injured neurons induced by transient ischemia. Our previous report showed that the trap of proteasome in the protein aggregates was a reason to lead to the reduction of proteasome activity. However, the patterns of proteasome entered into protein aggregates are not clear. In this study, we used a global ischemia model, Hematoxylin-Eosin staining, differential centrifuge, proteasome activity assay, sucrose gradient density centrifuge, and Western blot analysis to investigate this problem. Our results show that there are two aggregation patterns of proteasome after transient ischemia and reperfusion. One is that 26S proteasome is trapped by protein aggregates as a whole unit, and the other is that 19S or 20S is trapped in the protein aggregates, respectively, after 26S disassociates.

Proteasome alteration and delayed neuronal death in hippocampal CA1 and dentate gyrus regions following transient cerebral ischemia

BACKGROUND： Proteasome dysfunction has been reported to induce abnormal protein aggregation and cell death. OBJECTIVE： To investigate the effect of proteasome changes on delayed neuronal death in CA1 and dentate gyrus （DG） regions of the rat hippocampus following transient cerebral ischemia. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment. The study was performed at the Department of Biochemistry and Molecular Biology, Norman Bethune Medical College of Jilin University, from September 2006 to May 2008. MATERIALS： Rabbit anti-19S S10B polyclonal antibody was purchased from Bioreagents, USA; propidium iodide and fluorescently-labeled goat anti-rabbit IgG were purchased from Jackson Immunoresearch, USA; hematoxylin and eosin staining solution was purchased from Sigma, USA; LSM 510 confocal microscope was purchased from Zeiss, Germany. METHODS： A total of 40 healthy Wistar rats, male, 4 months old, were randomly divided into sham surgery group （n = 8） and model group （n = 32）. Ischemic models were established in the model group by transient clamping of the bilateral carotid arteries and decreased blood pressure. After 20 minutes of global ischemia, the clamp was removed to allow blood flow for 30 minutes, 4, 24 and 72 hours, respectively, with 8 rats at each time point. The bilateral carotid arteries were not ligated in the sham surgery group. MAIN OUTCOME MEASURES： Neuronal death in the CA1 and DG regions was observed by hematoxylin-eosin staining. Proteasome expression in CA1 and DG region neurons was detected by immunohistochemistry. RESULTS： Hematoxylin-eosin staining showed neuronal death in the CA1 region alone at 72 hours of reperfusion following ischemia. In comparison to the sham surgery group, a significant decrease in proteasome expression was observed, by immunohistochemistry, in the CA1 and DG regions in the model group, following 30 minutes, 4, 24, and 72 hours of reperfusion （P 〈 0.01）. After 72 hours of reperfusion following ischemia, proteasome expression had almost completely disappeared in the CA1 region. In contrast, neurons of the DG region showed minimized proteasome expression at 24 hours, with a slight increase at 72 hours （P 〈 0.01）. CONCLUSION： The alteration of proteasome following ischemia/reperfusion in the neurons of hippocampal CA1 and DG regions reduces the ability of cells to degrade abnormal protein, which may be an important factor resulting in delayed neuronal death following transient cerebral ischemia.

The neuroprotection of electro-acupuncture via the PGC-1α/TFAM pathway in transient focal cerebral ischemia rats

ATP depletion is one of the pathological bases in cerebral ischemia.Electro-acupuncture(EA)is widely used in clinical practice for ischemia.However,the mechanism of EA remains unclear.The purpose of this study was to investigate whether EA could activate the AMPK/PGC-1α/TFAM signaling pathway and,consequently,increase the preservation of ATP in rats with ischemia.In this study,48 rats were randomly divided into four groups as a sham-operation control group(sham group),a middle cerebral artery occlusion group(MCAO group),an EA group,and an EA group blocked by the AMPK inhibitor compound C(EA+CC group)(N=12/group).The rats of the EA group and EA+CC group received the EA treatment for 7 days.The rats that belonged in the two remaining groups were only grasped in the same condition.Then,their brain tissues were collected for further detection.When compared with other groups,EA significantly reduced neurological deficits score and increased motor function.The cerebral infarction volume was significantly reduced in the EA group according to TTC staining.With western blot,we found that EA improved the ratio of p-AMPKα/AMPKα(P<0.05),however,there is no difference between the MCAO group and sham group(P>0.05).In addition,EA also increased the expression of PGC-1αand TFAM(all P<0.05).By Elisa,we observed that EA increased the preservation of ATP(P<0.05)and mitochondrial respiratory enzymes,including Complex I(P<0.05),Complex IV(P<0.05),but not Complex III(P>0.05).In summary,we conclude that EA may protect against ischemic damage in MCAO rats,improve the preservation of ATP and mitochondrial respiratory enzymes.This effect may be positively regulated by the activation of the PGC-1α/TFAM signaling pathway.

Autophagy Elicits Neuroprotection at the Subacute Phase of Transient Cerebral Ischaemia but Has Few Effects on Neurological Outcomes After Permanent Ischaemic Stroke in Rats

Objective Autophagy was prominently activated by cerebral ischaemia.This study was to investigate the exact role of autophagy in ischaemic stroke.Methods Two rat models of transient middle cerebral artery occlusion(tMCAO)and permanent MCAO(pMCAO)were prepared.The brain tissues in the penumbra were obtained to observe the dynamic variations of autophagy activity with Beclin1 and LC3 antibodies by Western blotting.At the characteristic time points,when autophagy activity was markedly elevated or reduced,the autophagy activation signaling was intervened with rapamycin and 3-methyladenine,respectively.Thereafter,key proteins in the autopahgic/lysosomal pathway were detected with the antibodies of LC3,p62,ubiquitin,LAMP-1 and cathepsin B.Meanwhile,TTC staining,neurological score and immunofluorescence were performed to evaluate brain infarct volume,neurological deficit and neuron survival,respectively.Results Both Beclin1 and LC3 expression levels were remarkably altered at 6 h,12 h,2 days and 7 days after tMCAO.Interestingly,the dynamic changes of autophagy activity following pMCAO were identical to those after tMCAO.Neither autophagy induction nor autophagy inhibition was able to ameliorate the pMCAO-induced neurological injury due to lysosomal dysfunction,as indicated by low levels of LAMP-1 and cathepsin B,accompanied with the accumulation of LC3-II,ubiquitin and insoluble p62.Comparatively,autophagy induction elicited overt neuroprotection at 2 and 7 days after tMCAO,and this neuroprotection might be elicited by the enhancement of autophagy flux.Conclusion Our study suggests that autophagy confers neuroprotection at the subacute phase of tMCAO but has few effects on neurological outcomes after pMCAO.

DNA hypomethylation promotes learning and memory recovery in a rat model of cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury impairs learning and memory in patients.Studies have shown that synaptic function is involved in the formation and development of memory,and that DNA methylation plays a key role in the regulation of learning and memory.To investigate the role of DNA hypomethylation in cerebral ischemia/reperfusion injury,in this study,we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery and then treated the rats with intraperitoneal 5-aza-2′-deoxycytidine,an inhibitor of DNA methylation.Our results showed that 5-aza-2′-deoxycytidine markedly improved the neurological function,and cognitive,social and spatial memory abilities,and dose-dependently increased the synaptic density and the expression of SYP and SHANK2 proteins in the hippocampus in a dose-dependent manner in rats with cerebral ischemia/reperfusion injury.The effects of 5-aza-2′-deoxycytidine were closely related to its reduction of genomic DNA methylation and DNA methylation at specific sites of the Syp and Shank2 genes in rats with cerebral ischemia/reperfusion injury.These findings suggest that inhibition of DNA methylation by 5-aza-2′-deoxycytidine promotes the recovery of learning and memory impairment in a rat model of cerebral ischemia/reperfusion injury.These results provide theoretical evidence for stroke treatment using epigenetic methods.

Effect of Chinese Patent Medicine Naodesheng against Repeated Transient Global Cerebral Ischemia in Mice

Objective To investigate the therapeutic effect and possible mechanisms of Chinese ptent medicine Naodesheng（NDS） on repeated transient global cerebral ischemia（GCI） in mice. Methods The repeated transient GCI mice were induced by bilateral carotid arteries ligation, and were randomly divided into model group, Sham group without arteries ligation, NDS groups（1.25 and 2.5 g/kg） and positive control（vinpocetine 3.1 mg/kg, VP） group. After oral administration once daily for successive 7 d, the transient GCI was induced. The degree of neurological deficit, histological changes, and neurons loss in the hippocampus were evaluated. In order to investigate the possible mechanisms, the oxidative stress and inflammatory factor were measured after 24 h of GCI. Comparison among multiple groups was performed with one-way analysis of variance（ANOVA）. Results NDS could significantly alleviate the neurological function impairment, histological injury, and neurons loss, increase the superoxide dismutase（SOD） activity, decrease the content of malondialdehyde（MDA）, and reduce inflammatory factor in the ischemic brain tissue. Conclusion NDS could significantly reduce brain injury induced by global ischemia, and its mechanism is closely associated with anti-oxidation and anti-inflammation.

Neuronal ERCC6 mRNA expression in rat brain induced by a transient focal cerebral ischemia

目的：观察缺血再灌注损伤对转录修复耦联因子（ＥＲＣＣ６）ｍＲＮＡ表达水平的影响．方法：在大鼠大脑中动脉栓塞模型上结合Ｎｏｒｔｈｅｒｎ杂交，原位杂交和共聚焦激光扫描显微镜的方法观察脑内ＥＲＣＣ６ｍＲＮＡ的表达，并进行细胞定位分析．结果：缺血再灌注损伤后，在缺血中心及边周区的ＥＲＣＣ６ｍＲＮＡ表达，２天时开始增加，３天达峰值，７天开始下降．ＥＲＣＣ６ｍＲＮＡ主要在缺血侧的神经元上表达，少数在星型胶质细胞上表达．结论：缺血侧神经元和神经胶质细胞上ＥＲＣＣ６ｍＲＮＡ表达增加，这提示了损伤后神经细胞的ＤＮＡ自身修复能力被增强．

A novel phenotype of B cells associated with enhanced phagocytic capability and chemotactic function after ischemic stroke

Accumulating evidence has demonstrated the involvement of B cells in neuroinflammation and neuroregeneration.However,the role of B cells in ischemic stroke remains unclear.In this study,we identified a novel phenotype of macrophage-like B cells in brain-infiltrating immune cells expressing a high level of CD45.Macrophage-like B cells chara cterized by co-expression of B-cell and macrophage markers,showed stronger phagocytic and chemotactic functions compared with other B cells and showed upregulated expression of phagocytosis-related genes.Gene Ontology analysis found that the expression of genes associated with phagocytosis,including phagosome-and lysosome-related genes,was upregulated in macrophage-like B cells.The phagocytic activity of macrophage-like B cells was ve rified by immunostaining and three-dimensional reconstruction,in which TREM2-labeled macrophage-like B cells enwrapped and internalized myelin debris after cerebral ischemia.Cell-cell interaction analysis revealed that macrophage-like B cells released multiple chemokines to recruit peripheral immune cells mainly via CCL pathways.Single-cell RNA sequencing showed that the transdiffe rentiation to macrophage-like B cells may be induced by specific upregulation of the transcription factor CEBP fa mily to the myeloid lineage and/or by downregulation of the transcription factor Pax5 to the lymphoid lineage.Furthermore,this distinct B cell phenotype was detected in brain tissues from mice or patients with traumatic brain injury,Alzheimer’s disease,and glioblastoma.Overall,these results provide a new perspective on the phagocytic capability and chemotactic function of B cells in the ischemic brain.These cells may serve as an immunotherapeutic target for regulating the immune response of ischemic stroke.

Overexpression of mitogen-activated protein kinase phosphatase-1 in endothelial cells reduces blood-brain barrier injury in a mouse model of ischemic stroke

Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.

Neuroprotective effect of ischemic preconditioning in focal cerebral infarction: relationship with upregulation of vascular endothelial growth factor

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.