海马区星形胶质细胞的活化状态与缺血耐受性关系的研究

目的：观察海马区星形胶质细胞的活化与缺血耐受性的关系。方法：钳夹沙土鼠的双侧颈总动脉制造脑缺血模型,尼氏染色及免疫荧光法染色,观察海马锥体细胞迟发性神经元坏死及抗胶质纤维酸性蛋白（ＧＦＡＰ）染色的改变。结果：脑缺血组,ＣＡ１区锥体细胞几乎全产中丧失,只见很量少的细胞残存,零星散在分布;预缺血组,ＣＡ１区锥体细胞少部分丧失,大部分幸存。对照组有少量微弱的ＧＦＡＰ染色阳性细胞;脑缺血组有些ＧＦＡＰ染色     

脑缺血海马CA1区5-HT变化的免疫组织化学研究

目的：观察脑缺血及缺血再灌流海马ＣＡ１区５－ＨＴ的变化，探讨脑缺血海马ＣＡ１区神经元损伤与５－ＨＴ变化的关系。方法：用免疫组织化学ＡＢＣ法及图像分析技术对沙土鼠脑缺血海马ＣＡ１区５－ＨＴ含量变化进行研究。结果：（１）脑缺血１０ｍｉｎ时，沙土鼠海马ＣＡ１区５－ＨＴ免疫反应阳必纤维的平均光密度值（ＯＤ）与对照组比较无显著性差异。而缺血３０ｍｉｎ时，ＯＤ值则下降，４ｈ时下降得更多，Ｐ〈０．０５。（２）脑     

阿托品减轻大鼠脑缺血后再灌流损害机制的初步探讨

为探讨乙酰胆碱（ａｃｅｔｙｌｃｈｏｌｉｎｅ，Ａｃｈ）在神经元缺血性损害中的作用和机制，本实验观察了Ａｃｈ能Ｍ受体拮抗剂阿托品对大鼠脑缺血再灌注损害的影响，发现阿托品（２５ｍｇ／ｋｇ，ｂｗ，ｉｐ）可明显减轻大鼠前脑缺血后再灌流所致海马ＣＡ１区神经元迟发性损害，减小大鼠大脑中动脉阻塞后再灌流损害范围，而对局部皮质血流变化无影响，表明阿托品对缺血脑组织的保护作用不是由于改善了局部脑血流，提示Ａｃｈ参与神     

沙土鼠及大鼠局部脑缺血时血小板活化因子的变化

目的：血小板活化因子（ＰＡＦ）拮抗剂能改善局部脑缺血所致功能和组织损伤,本文在沙土鼠单侧脑缺血及大鼠大脑中动脉凝闭的局部脑缺血观察了缺血后大脑组织ＰＡＦ的变化。方法：ＰＡＦ的测定采用薄层层析进行ＰＡＦ分离提取,用生物法测定ＰＡＦ含量的变化。结果：１沙土鼠右侧颈总动脉结扎３ｈ再灌２ｈ,右侧大脑组织ＰＡＦ含量明显高于左侧。２大鼠左侧脑中动脉凝闭后４８ｈ,左侧大脑组织ＰＡＦ含量明显高于右侧。结论：ＰＡＦ在局部脑缺血继发神经元损伤中可能有一定作用。     

大脑5－HT的变化及5－HT_2受体拮抗剂赛庚啶对沙土鼠脑缺血的影响

本文研究大脑组织５－ＨＴ及其代谢产物变化以及５－ＨＴ＿２受体拮抗剂赛庚啶对脑缺血损伤的防治作用。实验共分三部分，结果是：（１）在沙土鼠急性前脑缺血模型证明，缺血１０ｍｉｎ，３０ｍｉｎ，及缺血３０ｍｉｎ再灌２ｈ，可见脑组织５－ＨＴ减少，说明脑缺血时脑组织释放５－ＨＴ增加而摄取减少，５－ＨＴ代谢产物５ＨＩＡＡ缺血后也见减少，但再灌后明显增加。（２）５－ＨＬ＿２受体拮抗剂赛庚啶可减轻沙土鼠缺血５ｍｉｎ再灌７天后海马ＣＡ＿１区神经元迟发性损伤，给赛庚啶组ＣＡ＿１区神经元数为１６８．７９±６２．５／ｍｍ，而生理盐水对照组为８４．７２±８７．３１／ｍｍ。（３）赛庚啶对沙土鼠单侧脑缺血能减少脑组织水及钠含量改善脑水肿及减少脑组织Ｃａ￣（２＋）含量。从５－ＨＴ＿２受体拮抗剂的作用说明，５－ＨＴ可通过５－ＨＴ＿２介导加重脑缺血时神经元损伤，加重脑水肿和脑组织Ｃａ＿（２＋）聚积，５－ＨＴ＿２受体拮抗剂可减轻缺血性脑损伤。     

后适应对树鼩不同脑缺血模型同一"时间窗"海马神经元保护的比较

目的: 观察缺血后适应(PC)对血栓性脑缺血(TC)及大脑中动脉闭塞(MCAO)2种脑缺血模型同一"时间窗"的脑保护效果,并探讨其可能机制。方法: 建立树鼩TC及MCAO脑缺血模型,于脑缺血后4 h夹闭同侧颈总动脉实施缺血PC。用TTC染色显示皮层梗塞面积,采用电镜及激光多普勒(LD)技术分别观察脑缺血后4 h、24 h及72 h海马CA1区神经元超微结构及局部脑血流(rCBF)的变化,比较PC对2种中风模型海马 rCBF和神经元超微结构的影响。结果: 脑缺血后海马CA1区神经元的超微结构改变以线粒体肿胀、嵴断裂以及内质网扩张为主,MCAO的梗塞面积和细胞损伤程度明显高于TC组,且PC缓减TC组海马线粒体损伤的作用较MCAO的明显。TC和MCAO后海马rCBF明显降低,TC组rCBF的降低以24 h明显(P＜0.01),而MCAO组rCBF的降低则以72 h明显(P＜0.01)。脑缺血后4 h实施PC可改善TC组海马rCBF(P＜0.01)和减轻线粒体损伤,而MCAO组rCBF及神经元形态学改善不明显。结论: 脑缺血后4 h实施缺血PC能有效对抗缺血性脑损伤,其脑保护效果与rCBF的增加有关。缺血PC对TC组的脑保护作用较MCAO组明显。     

亚硒酸钠对沙土鼠脑缺血再灌注损伤的海马CA1区神经元超微结构的影响

目的探讨亚硒酸钠对沙土鼠脑缺血再灌注损伤的海马CA1区神经元超微结构的影响。方法采用夹闭双侧颈动脉法制备沙土鼠前脑缺血再灌注模型,双重染色,电镜下观察各组海马CA1区神经元的超微结构变化。TUNEL染色光镜下观察和计数凋亡神经元,计算凋亡密度。结果硒处理组沙土鼠脑缺血再灌注后,神经元超微结构的病理形态损伤减轻,凋亡细胞减少,与对照组比较有显著差异(P<0.01)。结论亚硒酸钠对沙土鼠脑缺血再灌注损伤的海马CA1区神经元超微结构及凋亡细胞具有保护作用,可能存在对脑缺血耐受的机制。     

丹参酮对大鼠实验性脑梗塞的防治作用

凝闭大鼠一侧大脑中动脉、造成局灶性脑梗塞后24小时,大鼠外周中性粒细胞活性增强;缺血区脑组织脂质过氧化损伤严重;TTC染色后可见边界明显的脑坏死区。丹参酮可抑制脑缺血所致的中性粒细胞吞噬化学发光增强,减少白细胞在缺血区内的浸润,减轻脑组织脂质过氧化损伤,保护SOD活性,缩小梗塞范围。其抑制粒细胞功能激活与减轻脑缺血性损伤之间有显著的正相关关系。这一作用与地塞米松相似。提示:丹参酮抑制白细胞功能的作用可能是其防治脑梗塞的机制之一。     

bFGF对局灶性脑缺血大鼠脑组织ERK表达的影响

目的研究大鼠脑缺血再灌注后对胞外信号调节激酶(extracellular signal-regulated kinase,ERK)表达的影响,探讨碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对脑组织缺血再灌注神经元ERK的调节作用及机制。方法应用线栓法制作大鼠局灶性脑缺血再灌注模型,大脑中动脉阻塞2 h再灌注损伤24 h,采用TUNEL法、免疫组化检测海马及皮质内神经元凋亡和ERK的表达。结果 sham组鼠海马及大脑皮质偶见凋亡细胞,大脑皮质及海马神经元内少见ERK免疫反应阳性细胞;I/R组鼠海马及皮质神经元凋亡增加,缺血再灌注损伤后大脑皮质及海马神经元内ERK阳性表达明显高于假手组;bFGF组鼠海马及皮质神经元凋亡减少,皮质及海马神经元内ERK表达较I/R组明显增加。结论 bFGF显著减少缺血神经元凋亡,上调脑缺血诱导的ERK表达,对脑缺血再灌注海马及皮质神经元的具有保护作用。     

氯碘羟喹对脑缺血沙土鼠海马神经元的保护作用

目的研究金属螯合剂氯碘羟喹(Clioquinol,CQ)对沙土鼠全脑缺血再灌注后海马CA3区锥体细胞的保护作用。方法无创动脉夹夹持沙土鼠双侧颈总动脉制备脑缺血模型,腹腔注射CQ 3d,应用金属自显影技术检测CQ对沙土鼠海马游离锌离子的螯合作用,TUNEL和caspase-3原位杂交分析CQ对脑缺血沙土鼠海马神经元凋亡的影响。结果脑缺血CQ处理组沙土鼠海马金属自显影阳性反应明显低于脑缺血溶剂对照组,脑缺血CQ处理组沙土鼠海马TUNEL和caspase-3阳性细胞数量明显低于脑缺血溶剂对照组。结论 CQ对沙土鼠海马游离锌离子有明显的螯合作用,可能与其对脑缺血再灌注损伤的保护作用有关。     

Monotherapy with dextromethorphan or tirilazad – but not a combination of both – improves outcome after transient focal cerebral ischemia in rats

Cell death after cerebral ischemia is mediated by a massive release of excitatory amino acids, generation of free radicals, and – a crucial step – calcium influx into cells. We examined the hypothesis that concurrent administration of drugs ameliorating brain damage via different mechanisms would result in a synergistic neuroprotective effect. The neuroprotective efficacy of two clinically available drugs – the N-methyl-d-aspartate and calcium-channel antagonist dextromethorphan (DM) and the antioxidant tirilazad – were studied in monotherapy and in combination in a rat model of transient focal ischemia. Male Sprague-Dawley rats were subjected to 90 min of middle-cerebral-artery occlusion by an intraluminal filament technique. The animals were randomly assigned to one of four treatments (n=10 each): (1) vehicle-treated controls, (2) DM, (3) tirilazad, (4) DM+tirilazad. Drugs or vehicles were administered 15 min before ischemia and at reperfusion. Local cerebral blood flow (LCBF) was bilaterally recorded by continuous laser Doppler flowmetry. Functional deficits were quantified by daily neurological examinations. Infarct volume was assessed planimetrically after 7 days. DM prevented post-ischemic hypoperfusion. Tirilazad did not influence LCBF. Monotherapy with DM or tirilazad improved neurological function and reduced infarct volume by 45% and 48%, respectively. Combination therapy failed to influence neurological recovery and infarct volume. Although, from pharmacological point of view, a synergistic neuroprotective effect is expected, combination of dextromethorphan and tirilazad may lead to mutual inhibition or potentiate adverse effects. Received: 3 December 1997 / Accepted: 22 May 1998     

DNA cleavage and proteolysis of microtubule-associated protein 2 after cerebral ischemia of different severity.

We report temporal profiles of cytoplasmic proteolysis and genomic DNA cleavage after cerebral ischemia of different severity in gerbils. Global forebrain ischemia by bilateral common carotid artery occlusion for 5 min with reperfusion, severe unilateral hemispheric ischemia by unilateral common carotid artery occlusion for 30 min with reperfusion, and complete ischemia by decapitation were used. The hippocampus was examined for proteolysis by using immunohistochemistry for microtubule-associated protein 2, DNA cleavage by using in situ nick-end labelling, and nuclear morphology by Hematoxylin staining. During evolution of delayed neuronal death after transient forebrain ischemia, loss of the immunoreaction for microtubule-associated protein 2 occurred almost in parallel with DNA cleavage in the CA1 region. In contrast, disappearance of the immunoreaction for microtubule-associated protein 2 was much faster than genomic DNA cleavage after unilateral hemispheric ischemia and reperfusion. The microtubule-associated protein 2 immunoreactivity was completely lost before development of changes in nuclear morphology or DNA cleavage after complete ischemia. The present study demonstrated the differences between necrosis and delayed neuronal death, but the nuclear morphology in the latter was not exactly the same as seen in apoptosis. Some elements of both necrotic and apoptotic machineries may work following transient ischemia, and the degree of ischemic insult may determine the character of cell death process.     

Potentiation of Akt and suppression of caspase-9 activations by electroacupuncture after transient middle cerebral artery occlusion in rats

Apoptosis is thought to be implicated in delayed neuronal cell death following transient forebrain ischemia. Recently, apoptosis in neurons induced by an inhibitor of serine/threonine (ser/thr) protein phosphatases (PPs) has been reported. In this study, we investigated the effect of transient forebrain ischemia on the expression of ser/thr PPs in the brain of Mongolian gerbils. At 24 h after 5-min bilateral carotid artery occlusion, Northern blotting analysis revealed the increase of PP1 mRNA expression in the vulnerable CA1 region of the hippocampus and striatum, but not in the cortex and CA3 region. In contrast, the protein level of PP1 detected by Western blotting analysis decreased in all regions. We conclude that the inhibition in PPs expression in the vulnerable regions may affect cell death after transient forebrain ischemia.     

Zinc translocation accelerates infarction after mild transient focal ischemia

Excess release of chelatable zinc (Zn(2+)) from central synaptic vesicles may contribute to the pathogenesis of selective neuronal cell death following transient forebrain ischemia, but a role in neurodegeneration after focal ischemia has not been defined. Adult male Long-Evans rats subjected to middle cerebral artery occlusion (MCAO) for 30 min followed by reperfusion developed delayed cerebral infarction reaching completion 3 days after the insult. One day after the insult, many degenerating cerebral neurons exhibited increased intracellular Zn(2+), and some labeled with the antibody against activated caspase-3. I.c.v. administration of the Zn(2+) chelator, EDTA saturated with equimolar Ca(2+) (CaEDTA), 15 min prior to ischemia attenuated subsequent Zn(2+) translocation into cortical neurons, and reduced infarct volume measured 3 days after ischemia. Although the protective effect of CaEDTA at this endpoint was substantial (about 70% infarct reduction), it was lost when insult severity was increased (from 30 to 60 min MCAO), or when infarct volume was measured at a much later time point (14 days instead of 3 days after ischemia).These data suggest that toxic Zn(2+) translocation, from presynaptic terminals to post-synaptic cell bodies, may accelerate the development of cerebral infarction following mild transient focal ischemia.     

尼古丁对大鼠局灶性脑缺血再灌注损伤的神经保护作用

目的:研究尼古丁对大鼠局灶性脑缺血再灌注损伤是否具有神经保护作用。方法:在大鼠大脑中动脉堵塞(MCAO)前30min给予腹腔注射尼古丁酒石酸盐溶液,观察局灶性脑缺血2h再灌注24h后,大鼠神经行为学评分及脑梗死容积的变化。结果:再灌注24h后,与单纯缺血再灌注组相比,给予尼古丁酒石酸盐溶液注射可以改善动物的神经行为学评分、减少脑梗死容积百分比(P0.05)。结论:尼古丁对大鼠局灶性脑缺血再灌注损伤具有神经保护作用。     

Bone marrow stromal cells can be delivered to the site of traumatic brain injury via intrathecal transplantation in rabbits

Bis(7)-tacrine, a promising anti-Alzheimer's dimer, has been shown to have multiple neuroprotective activities in vitro. Here, we investigate whether bis(7)-tacrine attenuates focal cerebral ischemic impairment in vivo. Cerebral ischemia was induced in Sprague-Dawley rats by transient (2h) middle cerebral artery occlusion (MCAO) followed by 24h of reperfusion. Bis(7)-tacrine administered intraperitoneally 15 min after ischemia dose-dependently improved neurological behavior deficits and reduced both cerebral infarct volume and edema. The TUNEL staining assay showed that bis(7)-tacrine attenuated neuronal apoptosis in the penumbral region. Compared with that for memantine, a moderately effective N-methyl-d-aspartate (NMDA) receptor antagonist with a similar affinity and potency to bis(7)-tacrine in blocking NMDA receptors, the therapeutic window for bis(7)-tacrine was wider and lasted up to 6h after the onset of ischemia. Bis(7)-tacrine did not affect physiological parameters or regional cerebral blood flow during either the occlusion period or the early reperfusion stage. In conclusion, bis(7)-tacrine dose- and time-dependently protected against acute focal cerebral ischemic insults, possibly through the drug's anti-apoptotic effects during multiple events in the ischemic cascade.     

D-JNKi, a peptide inhibitor of c-Jun N-terminal kinase, promotes functional recovery after transient focal cerebral ischemia in rats

The c-Jun-N-terminal kinase (JNK) pathway has been shown to play an important role in excitotoxic neuronal death and several studies have demonstrated a neuroprotective effect of D-JNKi, a peptide inhibitor of JNK, in various models of cerebral ischemia. We have now investigated the effect of D-JNKi in a model of transient focal cerebral ischemia (90 min) induced by middle cerebral artery occlusion (MCAo) in adult male rats. D-JNKi (0.1 mg/kg), significantly decreased the volume of infarct, 3 days after cerebral ischemia. Sensorimotor and cognitive deficits were then evaluated over a period of 6 or 10 days after ischemia and infarct volumes were measured after behavioral testing. In behavioral studies, D-JNKi improved the general state of the animals as demonstrated by the attenuation of body weight loss and improvement in neurological score, as compared with animals receiving the vehicle. Moreover, D-JNKi decreased sensorimotor deficits in the adhesive removal test and improved cognitive function in the object recognition test. In contrast, D-JNKi did not significantly affect the infarct volume at day 6 and at day 10. This study shows that D-JNKi can improve functional recovery after transient focal cerebral ischemia in the rat and therefore supports the use of this molecule as a potential therapy for stroke.     

Neuroprotective effects of zonisamide on cerebral ischemia injury via inhibition of neuronal apoptosis

It is known that neuronal apoptosis contributes to pathology of cerebral ischemia injury. Zonisamide (ZNS) has shown anti-apoptosis effects in recent studies. The present study investigated whether the anti-apoptotic effect can account for the neuroprotective action of ZNS on cerebral ischemia. Neuronal cells were maintained under oxygen-glucose deprivation conditions to simulate cerebral ischemia and treated with ZNS simultaneously. The apoptosis of the cells and expression of apoptosis-related proteins were investigated by flow cytometry and western blot analysis, respectively. A cerebral ischemia mouse model was created via middle cerebral artery occlusion, and the mice were treated with ZNS. Neurological deficit scores and infarct volumes of the cerebral ischemia mice were measured. The apoptosis status of the neuronal cells was evaluated by TUNEL staining. In vitro, the ZNS treatment inhibited both the apoptosis of the neuronal cells and apoptosis-related protein expression (caspase-3, caspase-8, and calpain-1) induced by the oxygen-glucose deprivation. The anti-apoptosis effect of ZNS could occur through the blocking of reactive oxygen species. Moreover, ZNS treatment significantly ameliorated neurological deficits and reduced infarct volumes in the cerebral ischemia mice model. In this study, ZNS exerted neuroprotective effects by inhibition of apoptosis in neuronal cells in cerebral ischemia. Therefore, ZNS might be a promising therapy for cerebral ischemia.     

UCF-101对大鼠脑缺血再灌注损伤的神经保护作用

目的观察UCF-101对大鼠脑缺血再灌注损伤后神经元凋亡及Caspase-9蛋白表达的影响,探讨UCF-101对缺血性脑损伤的神经保护作用。方法随机将大鼠分为假手术组、缺血再灌注组及UCF-101处理组。采用线栓法建立Wistar大鼠大脑中动脉闭塞(MCAO)2h再灌注模型,于再灌注后24h取脑,采用TTC法测梗死体积,TUNEL法检测神经元凋亡,免疫组化法观察脑组织神经元Caspase-9蛋白的表达。结果假手术组未见梗死现象,与假手术组比较,缺血再灌注组脑组织凋亡细胞数和Caspase-9的表达均明显升高(P0.05)。与缺血再灌注组相比,UCF-101处理组梗死体积明显缩小(P0.05),UCF-101处理组脑组织凋亡细胞数和Caspase-9的表达均明显减少(P0.05)。结论 UCF-101可能通过下调脑组织神经元Caspase-9蛋白的表达,抑制神经元的凋亡而发挥神经保护作用。     

局灶性脑缺血后鼠脑组织tPA基因表达及其与细胞凋亡

目的 探讨局灶性脑缺血后组织型纤溶酶原激活物（tＰＡ）基因的表达及其与细胞凋亡的 关系。方法 用原位杂交和免疫组织化学方法检测tＰＡ基因在大鼠局灶性脑缺血（大脑中 动脉阻塞）后的表达,用ＴＵＮＥＬ法检测缺血不同时间的细胞凋亡状况。结果 脑缺血６h缺血中心部位的胶质细胞和梗死灶周边缺血半影区的神经元均观察到tＰＡ免疫反应性信号,在大脑皮层后肢体区、顶皮层区、海马区和齿状回可见凋亡细胞,但缺血１８h缺血侧神