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。     

大脑5—HT的变化及5—HT2受体拮抗剂赛庚啶对沙土鼠脑缺血…

本文研究大脑组织５－ＨＴ及其代谢产物变化以及５－ＨＴ２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缺血后出见减少，但财灌后明显增加。（２）５－ＨＴ２受体拮抗剂赛庚啶可减轻沙土鼠缺血５ｍｉｎ再灌７     

脑缺血时中缝背核5-HT变化的免疫组化观察

目的：探讨沙土鼠有离缺血时中缝背核神经元５－ＨＴ的变化。方法：用免疫组织化学ＡＢＣ法及图象分析对沙土鼠缺血不同时间以及缺血１０分钟后再灌不同时间其中缝背核神经元６－ＨＴ的变化进行研究。结果：脑缺血１０钟、３０分钟时,沙土鼠脑中缝背核５－ＨＴ阳性神经元的平均光密度值（ＯＤ）值与对照组比较无显著性差异;而缺血４小时时则明显降低,差异有显著性（Ｐ〈０．０５）,脑缺血１０分钟后,再灌流２０分钟,５－ＨＴ下     

脑缺血／再灌注后大鼠海马GABA、AchE水平和迟发性神经元损害关系的研究

为探讨海马ＧＡＢＡ、ＡｃｈＥ和迟发性神经元损害（ｄｅｌａｙｅｄｎｅｕｒｏｎａｌｄａｍａｇｅ，ＤＮＤ）的关系，观察了脑缺血／再灌注后大鼠海马亚区ＧＡＢＡ含量、ＡｃｈＥ活性和海马组织病理改变。发现再灌注５ｍｉｎ，海马亚区ＧＡＢＡ含量显著升高，再灌注１ｈ和６～１２ｈ，ＧＡＢＡ含量明显降低，ＣＡ＿１区更明显。再灌注５ｍｉｎ至１ｈ，海马亚区ＡｃｈＥ活性明显升高。再灌注４８ｈ后，光镜下见海马ＣＡ＿１区神经元出现缺血性改变，提示：（１）再灌注后，ＧＡＢＡ含量减少、海马内源性抑制降低可能是ＣＡ＿１区ＤＮＤ的因素之一。（２）再灌注早期ＡｃｈＥ活性升高，提示Ａｃｈ代谢变化可能和ＤＮＤ有关。（３）再灌注后ＧＡＢＡ和ＡｃｈＥ在海马各亚区的明显改变，提示ＣＡ＿１区选择性易损和递质代谢变化密切相关，而ＣＡ＿１区神经元本身的生理生化特性也起着重要的作用。     

右甲吗喃对脑缺血的实验治疗研究

目的和方法：在沙土鼠通过夹闭双侧颈总动脉复制短暂性脑缺血神经元迟发性坏死,以海马ＣＡ１区神经元坏死为指标;在大鼠采用凝闭大脑中动脉复制局部脑缺血,以缺血区脑组织钠、水、钙含量及梗塞面积为指标;观察非竞争性、低亲和力兴奋性氨基酸拮抗剂右甲吗喃对抗脑缺血的作用。结果：右甲吗喃能提高沙土鼠脑缺血后海马ＣＡ１区神经元存活数;能降低大鼠大脑中动脉闭塞后缺血区水、钠及钙含量,缩小梗塞面积。结论：右甲吗喃能减轻脑缺血后神经元死亡（即凋亡）;并通过减轻脑水肿,缩小梗塞面积,改善大鼠局部脑缺血时缺血性脑损伤。     

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     

氟烷和七氟醚对缺血再灌注心肌功能和氧自由基的影响

目的：研究１５肺泡最小浓度（ＭＡＣ）的氟烷和七氟醚对缺血再灌注心肌功能和氧自由基的影响。方法：应用离体大鼠心脏Ｌａｎｇｅｎｄｏｒｆ逆行灌注模型研究１５ＭＡＣ的氟烷、七氟醚对心肌缺血前后心功能的影响,测定缺血前、缺血１０ｍｉｎ、复灌３０ｍｉｎ３个不同时间的心肌超氧化物歧化酶（ＳＯＤ）活性和丙二醛（ＭＤＡ）含量。结果：七氟醚不同程度地抑制心肌收缩功能。缺血１０ｍｉｎ时,七氟醚组ＳＯＤ酶活性明显下降,ＭＤＡ含量显著升高。缺血２５ｍｉｎ复灌３０ｍｉｎ后,二药均能促进心肌功能和ＳＯＤ酶活性恢复,抑制ＭＤＡ生成,其中七氟醚的作用较为明显。结论：二药对缺血再灌注心肌具有一定的保护作用,七氟醚优于氟烷。     

脑缺血／再灌注后大鼠海马GABA,AchE水平和迟发性神经元损害…

为探讨海马ＧＡＢＡ，ＡｃｈＥ和迟发性神经元损害的关系，观察了脑缺血／再灌注后大鼠海马亚区ＧＡＢＡ含量，ＡｃｈＥ活性和海马组组织病理改变。发现再灌注５ｍｉｎ，海马亚区ＧＡＢＡ含量显著升高，再灌注１ｈ和６－１２ｈ，ＧＡＢＡ含量明显降低，ＣＡ１区更明显。再灌注５ｍｉｎ至１ｈ，海马亚区ＡｃｈＥ活性明显长高。再注４８ｈ后，光镜下见海马ＣＡ１区神经元出现缺血性改变，提示：（１）再灌注后，ＧＡＢＡ含量减少，海马     

全脑暂时性缺血诱导原癌基因蛋白（FOS）在大鼠海马结构表达的特征

用免疫组化方法，对大鼠暂时性全脑缺血诱导的ｃ－ｆｏｓ原癌基因蛋白（Ｆｏｓ）在海马表达的分布，强度和时间过程等特征进行了观察。结果表明：缺血４０ｍｉｎ再循环后２ｈ，首先在海马齿伏回转折部的颗粒细胞和下托诱导出Ｆｏｓ表达，５－８ｈ达到高峰，８ｈ后锐减并逐步消失。ＣＡ４和ＣＡ３区的Ｆｏｓ表达在缺血再循环后３ｈ出现，５ｈ达到高峰，持续至２４ｈ消失。而在ＣＡ２和ＣＡ１区，Ｆｏｓ表达最弱，最晚（５ｈ才出现 ）     

小檗碱对大鼠全脑缺血后海马的保护作用

本研究室以往曾发现小檗碱具有预防脑缺血短期（７ｄ）再灌流海马ＣＡ１迟发性神经元坏死（ＤＮＤ）的作用。本研究采用Ｐｕｌｓｉｎｅｌｌｉ－Ｂｒｉｅｒｌｅｙ四血管阻塞（４ＶＯ）致大鼠全脑缺血模型，观察了小檗碱对脑缺血（２ｍｉｎ）长期再灌流后海马的影响，并对脑缺血经短、长期再灌流对照及用药组大鼠进行了Ｍｏｒｒｉｓ水迷宫学习记忆能力检测。结果显示，小檗碱能有效的保护海马ＣＡ１区锥体细胞免于脑缺血后ＤＮＤ，经长期（３个月）再灌流后这种保护作用依然存在，细胞密度为１６８个／ｍｍ，占正常８０．５％；对脑缺血经长期再灌流引起的海马ＣＡ２、ＣＡ３、ＣＡ４继发性神经无死亡也有明显的对抗作用。脑缺血短期（１０ｄ）再灌流后，大鼠表现为明显的学习障碍，潜伏期延长，但经多次训练后，大鼠在原平台象限泳距比其它非平台象限都显著长，表明尚有良好的空间记忆能力；脑缺血经长期再灌流后，其空间学习障碍加重、记忆能力也受到严重影响。而用药组缺血大鼠无论短期或长期再灌流后，均保存了良好的空间学习、记忆能力。表明脑缺血经长期再灌流后，海马的形态和学习、记忆能力比短期再灌时将进一步受损害，而小檗碱不但对短期再灌流有保护作用，对长期再灌流的进一步损害也有明显的?     

浅低温对沙土鼠脑缺血再灌后能量代谢及羟自由基产生的影响

目的:研究浅低温对沙土鼠脑缺血再灌后海马三磷酸腺苷(ATP)、二磷酸腺苷(ADP)、腺苷酸(AMP)含量和羟自由基(OH·)产生以及延迟性神经元死亡(DND)的影响。方法:沙土鼠前脑缺血再灌注模型,脑缺血10min。应用高效液相结合电化学检测器测定海马OH·含量,高效液相及紫外检测器测定ATP、ADP、AMP含量,组织学检查判断DND。结果:缺血再灌96h,浅低温+缺血再灌组DND数目明显少于缺血再灌组。缺血再灌6h,浅低温+缺血再灌组海马2,3-二羟基苯甲酸(2,3-DHBA)含量明显低于缺血再灌组(P＜0.01),但在缺血再灌48和96h,3组间2,3-DHBA含量相比差异无显著性。脑缺血再灌6h,3组间ATP、ADP、AMP含量相比差异无显著性。在再灌48和96h,浅低温+缺血再灌组海马ATP、ADP、AMP含量明显高于缺血再灌组。结论:浅低温可能通过改善脑缺血后细胞能量代谢而减少DND。     

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.     

沙土鼠短暂性脑缺血后海马迟发性神经元死亡机理的研究

本实验通过结扎沙土鼠双侧颈总动脉20分钟后再灌流2天或7天造成海马迟发性神经元死亡(DND)模型,检测背侧海马Ca~(2 )及脂质过氧化物含量的变化,并用海马CA_1区神经元密度作为指标,观察尼莫地平及超氧化物歧化酶(SOD)对海马DND的影响。结果:再灌流2天后背侧海马组织Ca~(2 )及MDA含量增加;尼莫地平及SOD均可改善海马CA_1区DND,使海马CA_1区神经元密度增加。本实验提示:Ca~(2 )及氧自由基导致的脂质过氧化物在短暂性脑缺血后海马DND的发生中起重要作用,钙拮抗剂及自由基清除剂对海马DND有保护作用。     

多重脑震荡大鼠5-羟色胺能神经纤维变化

目的:研究多重脑震荡(MCC)与大鼠认知记忆相关脑区5-羟色胺(5-HT)能神经纤维变化的规律,以探讨MCC大鼠认知行为障碍的神经生物学基础。方法:应用自制单摆式机械打击装置构建MCC大鼠模型,免疫组织化学及半定量方法研究MCC后大鼠5-HT能神经纤维的变化。结果:前额叶皮质、中隔区、丘脑、海马CA1和CA3区5-HT能神经纤维免疫反应阳性物在伤后2d组反应达高峰,杏仁体、海马CA2和CA4区在伤后4d组免疫反应了阳性最强;顶叶皮质、梨状皮质及伏隔核内侧在伤后8d组反应最强。5-HT纤维密度在中隔区和伏隔核内侧以伤后2d最高,杏仁体区以伤后1d最高,大脑皮质和丘脑5-HT纤维密度在伤后各损伤组与对照组相比无显著性差异。结论:MCC可引起与认知功能有关脑区的5-HT表达增高,5-HT的高表达可能由脑损伤后神经元过度兴奋所引起的神经递质紊乱造成,而这种紊乱可能影响大鼠的认知功能。     

NGF对局灶性脑缺血再灌注大鼠海马和顶叶皮质内CREB mRNA表达的影响

探讨外源性神经生长因子(nervegrowthfactor,NGF)对局灶性脑缺血再灌注大鼠海马和顶叶皮质内的cAMP反应元件结合蛋白(cyclicAMPresponseelementbindingprotein,CREB)mRNA表达的影响。用线栓法制作大鼠局灶性脑缺血再灌注模型,运用原位杂交和图像分析技术检测大鼠缺血侧海马CA1区和顶叶皮质内CREBmRNA的表达。结果显示:缺血再灌注组缺血侧海马CA1区和顶叶皮质CREBmRNA阳性反应产物平均光密度(OD)比假手术组减少(P<0.05),NGF组CA1区和顶叶皮质内的CREBmRNA阳性产物平均光密度高于缺血再灌注组(P<0.05)。本研究结果提示NGF可以上调局灶性脑缺血再灌注大鼠海马和顶叶皮质缺血神经元CREBmRNA的表达,NGF对缺血神经元的保护作用可能通过激活CREB的转录与翻译,从而启动一系列信号通路来实现。     

养血清脑颗粒对蒙古沙鼠全脑缺血再灌注后海马CA1区神经元的治疗作用

目的 探讨蒙古沙鼠全脑缺血再灌注后养血清脑颗粒(Yangxueqingnaokeli,YXQNKL)的治疗作用.方法 采用蒙古沙鼠两侧颈总动脉结扎法,缺血30min再灌注5d模型(分为假手术组、缺血再灌注组、养血清脑颗粒治疗组).用Nissl染色法观察海马CA1区神经元的形态和数量,用免疫组织化学方法观察海马CA1区神经元神经钙离子感应蛋白1(NCS-1)、天冬氨酸特异性半胱氨酸蛋白酶3(caspase-3)和谷氨酸盐合成酶(Glusyn)的表达情况.结果 与缺血再灌注组比较,缺血再灌注 0.4g/kg养血清脑颗粒治疗组和缺血再灌注 0.8g/kg养血清脑颗粒治疗组Nissl染色显示海马CA1区神经元数量明显增加(P＜0.05);免疫组织化学法显示海马CA1区神经元细胞NCS-1、caspase-3和Glusyn的阳性细胞数明显减少(P＜0.05).结论 全脑缺血再灌注后,给予养血清脑颗粒能显著增加海马CA1区神经元数量,这与其减少海马CA1区神经元NCS-1、caspase-3和Glusyn的表达有密切的联系.     

Differential effects and changes of ceruloplasmin in the hippocampal CA1 region between adult and aged gerbils after transient cerebral ischemia

In this study, we examined the differential effects and changes of ceruloplasmin between adult and aged gerbil hippocampus after transient forebrain ischemia. Ceruloplasmin in the hippocampal CA1 region of adult and aged gerbils was significantly changed after ischemia/reperfusion. Whereas, it was not significantly changed in the CA2/3 region compared to the CA1 region after ischemia. Ceruloplasmin immunoreactivity and its protein level in aged gerbil CA1 region were higher than those in adult gerbil CA1 region. Ceruloplasmin in the CA1 region was highest in adult gerbils and aged gerbils at 24h and 12h after transient ischemia, respectively. At these time points, strong ceruloplasmin immunoreactivity was observed in CA1 pyramidal cells. Thereafter, ceruloplasmin was decreased with time after ischemia. Four days after ischemia/reperfusion, ceruloplasmin immunoreactivity in both adult and aged gerbils was expressed in astrocytes in the CA1 region. Ceruloplasmin treatment in adult ischemic gerbils showed strong protective effect against ischemic damage in CA1 pyramidal cells compared to that in aged ischemic gerbils. We conclude that ceruloplasmin early increases in the aged gerbil CA1 region compared to that of the adult gerbil CA1 region may be associated with the earlier induction of reactive oxygen species, and ceruloplasmin shows strong neuroprotective effects in adults compared to those in aged gerbils.     

Delayed treatment with nimesulide reduces measures of oxidative stress following global ischemic brain injury in gerbils

Metabolism of arachidonic acid by cyclooxygenase is one of the primary sources of reactive oxygen species in the ischemic brain. Neuronal overexpression of cyclooxygenase-2 has recently been shown to contribute to neurodegeneration following ischemic injury. In the present study, we examined the possibility that the neuroprotective effects of the cyclooxygenase-2 inhibitor nimesulide would depend upon reduction of oxidative stress following cerebral ischemia. Gerbils were subjected to 5 min of transient global cerebral ischemia followed by 48 h of reperfusion and markers of oxidative stress were measured in hippocampus of gerbils receiving vehicle or nimesulide treatment at three different clinically relevant doses (3, 6 or 12 mg/kg). Compared with vehicle, nimesulide significantly (P<0.05) reduced hippocampal glutathione depletion and lipid peroxidation, as assessed by the levels of malondialdehyde (MDA), 4-hydroxy-alkenals (4-HDA) and lipid hydroperoxides levels, even when the treatment was delayed until 6 h after ischemia. Biochemical evidences of nimesulide neuroprotection were supported by histofluorescence findings using the novel marker of neuronal degeneration Fluoro-Jade B. Few Fluoro-Jade B positive cells were seen in CA1 region of hippocampus in ischemic animals treated with nimesulide compared with vehicle. These results suggest that nimesulide may protect neurons by attenuating oxidative stress and reperfusion injury following the ischemic insult with a wide therapeutic window of protection.