反复性脑缺血神经元选择性易损性的实验研究

目的　研究反复性脑缺血神经元选择性易损性。方法应用４５Ｃａ放射自显影及光镜对比观察大鼠反复性与单次性脑缺血神经元损害的密度和分布。结果　单次缺血易损部位主要为海马、新皮层、纹状体、丘脑、小脑、脑干等;反复缺血易损区的分布与单次缺血基本相似,但下丘和小脑对反复缺血抵抗,而丘脑腹侧和海马呈现显著的累积性损害。结论　反复性脑缺血神经元选择性易损性及其机制均有别于单次性脑缺血。     

胶质纤维酸性蛋白在老年痴呆大鼠海马中的表达

为探讨慢性缺血痴呆鼠学习减退与海马内星形胶质细胞表达的关系,基于老年大鼠慢性脑缺血痴呆模型,采用免疫组化技术及迷宫实验,定量分析海马星形胶质细胞变化与学习能力、记忆能力的关系。结果发现,慢性缺血痴呆鼠海马CAl区GFAP阳性细胞数目明显增多,胞体肥大,突起增粗、变长,与对照组相比有显著意义(P<0.05),Y型迷宫测试结果显示,痴呆组大鼠的学习、记忆能力与对照组相比,明显下降。提示海马星形胶质细胞可能参与慢性缺血痴呆大鼠的学习记忆功能。     

预缺血诱导大鼠CA1神经元中蛋白伴侣hsp70的表达并抑制蛋白聚集物的形成

目的 研究预缺血对蛋白伴侣hsp70表达和蛋白聚集物形成的影响,探讨其可能的脑保护机制.方法 采用大鼠双侧颈总动脉暂时夹闭法建立全脑缺血模型.大鼠分为3min缺血组,10min缺血组以及预缺血组.苏木素-伊红染色,光镜下随机计数分析预缺血后海马CA1区死亡神经元数量变化.免疫组织化学及激光扫描共聚焦显微镜法观察蛋白伴侣hsp70在CAI区神经元内的分布.差速离心分离细胞浆、细胞核及蛋白聚集物.蛋白印迹法检测不同缺血状态下海马CA1神经元内蛋白聚集物含量的变化,以及胞浆、胞核及蛋白聚集物内蛋白伴侣hsp70含量的变化.结果 组织学检查显示预缺血能够显著减少海马CA1区神经元死亡数量.预缺血诱导海马CA1区神经元内蛋白伴侣hsp70在再灌注后24h表达.预缺血处理后,海马CA1区神经元内蛋白聚集物显著减少.预缺血诱导的蛋白伴侣hsp70与再缺血形成的异常蛋白结合在一起并防止其聚集.结论 预缺血可能通过诱导蛋白伴侣hsp70的表达和抑制再缺血后蛋白聚集物的形成,减少再缺血引起的神经元死亡.     

缺血性Wistar大鼠痴呆模型的脑组织及血清微量和常量元素…

对Ｗｉｓｔａｒ大鼠反复缺血性痴呆模型的血清及脑组织中锌、铜、铁、硒、钙、镁元素进行了测定。结果显示：缺血性Ｗｉｓｔａｒ大鼠痴呆模型的脑组织中，锌，钙含量升高，镁含量降低、铜，铁，研究变化；血清中各元素含量也无变化。提示：在反复缺血灌注后的神经元损害过程中，脑组织局部存在钙、锌、镁的异常变化 。     

缺血性Wistar大鼠痴呆模型的脑组织及血清微量和常量元素研究

对Ｗｉｓｔａｒ大鼠反复缺血性痴呆模型的血清及脑组织中锌、铜、铁、硒、钙、镁元素进行了测定。结果显示：缺血性Ｗｉｓｔａｒ大鼠痴呆模型的脑组织中，锌、钙含量升高，镁含量降低，铜、铁、硒无变化；血清中各元素含量也无变化。提示：在反复缺血灌注后的神经元损害过程中，脑组织局部存在钙、锌、镁的异常变化。     

养血清脑颗粒对大鼠慢性脑缺血细胞凋亡及神经细胞突触结构的影响

目的 研究养血清脑颗粒对大鼠慢性脑缺血模型的神经细胞凋亡及突触结构的影响.方法 SD大鼠随机分为假手术对照组、慢性缺血组、慢性缺血+养血清脑颗粒治疗组、慢性缺血+养血清脑颗粒预防组.应用大鼠双侧颈总动脉结扎方法制备慢性脑缺血大鼠模型,应用流式细胞术检测细胞凋亡,透射电镜和图像分析观察并测定大鼠海马及皮质突触的形态参数.结果 流式细胞术显示脑缺血14天后,细胞凋亡明显增多,养血清脑颗粒可明显抑制细胞凋亡;缺血组可导致突触结构参数变化,而慢性缺血+养血清脑颗粒治疗组和慢性缺血+养血清脑颗粒预防组可明显减轻这一变化.结论 养血清脑颗粒对慢性脑缺血细胞凋亡及突触结构改变的抑制作用有可能对慢性脑缺血的病理改变起到预防和治疗的作用.     

血管性痴呆小鼠海马ERK2及p-ERK的表达特征

目的观察血管性痴呆（VD）小鼠海马中细胞外信号调节激酶（ERK2、p-ERK）的表达变化,探讨其在VD发病中的作用机制。方法采用双侧颈总动脉反复缺血-再灌注法制备小鼠VD模型,设立假手术组作为对照。术后第29、30天,经跳台试验和水迷宫试验对各组小鼠进行行为学成绩测试,用免疫组化方法观察各组小鼠海马CA1区ERK2及海马CA3区p-ERK的表达变化。结果VD模型小鼠学习、记忆成绩较假手术组显著下降（P〈0.05）;模型组小鼠海马CA1区ERK2的表达及海马CA3区p-ERK的表达较假手术组减少,差异有统计学意义（P〈0.05）。结论海马神经元内ERK的表达减少可能参与了血管性痴呆的发病机制,因此应用能促进ERK表达的药物可能成为治疗VD的有效方法之一。     

血管性痴呆小鼠海马细胞外信号调节激酶表达的变化

目的:观察血管性痴呆(VD)小鼠海马中细胞外信号调节激酶(ERK1、p-ERK)的表达特征,探讨其在VD发病中的作用机制。方法:采用双侧颈总动脉反复缺血-再灌注法制备小鼠VD模型,设立假手术组作为对照。术后第29、30天,经跳台试验和水迷宫试验对各组小鼠进行行为学成绩测试,用免疫组化方法观察各组小鼠海马CA1区ERK1及海马CA3区p-ERK的表达变化。结果:VD模型小鼠学习、记忆成绩较假手术组显著下降(P<0.05)。模型组小鼠海马CA1区ERK1的表达及海马CA3区p-ERK的表达较假手术组减少,均有显著性差异(P<0.05)。结论:海马神经元内ERK的表达减少可能参与了血管性痴呆的发病机制,因此应用能促进ERK表达的药物可能成为治疗VD的有效方法之一。     

Wistar鼠全脑反复缺血再灌流6脑区中精氨酸加压素含量…

精氨酸加压素（ＡＶＰ）是脑内重要的神经递质，本研究采用４血管关闭的方法，制造Ｗｉｓｔａｒ大鼠全脑反复缺血再灌流长期生存动物模型，然后利用放免方法测定了缺血后存活不同时间大鼠额叶，颞叶，海马，丘脑，纹状体，脑干６个脑区的ＡＶＰ含量。发现缺血即刻各脑区ＡＶＰ无显变化（Ｐ＞０．０５），缺血后１５天显著下降（Ｐ＜０．０１），３０天时继续下降（Ｐ＜０．０１），６０时变化方趋稳定，９０天和１８０天时和对照组比     

慢性脑缺血信号转导和转录激活因子-1的表达

目的 探讨慢性脑缺血大脑皮质及海马STAT-1的变化.方法 采用免疫组织化学和激光共聚焦方法观察慢性脑缺血大鼠脑中STAT-1蛋白表达变化.结果 STAT-1免疫反应阳性细胞在正常和假手术大鼠脑内发现有少量表达;缺血30d组,STAT-1蛋白阳性细胞分布于皮层及海马,细胞数量明显多于非缺血组,差异有统计学意义(P＜0.05).结论 STAT-1可能参与慢性脑缺血大鼠神经细胞死亡的诱导.     

粒细胞集落刺激因子对血管性痴呆大鼠海马神经细胞凋亡的影响

背景：研究发现，粒细胞集落刺激因子可激活脑内成体神经干细胞，刺激其增殖和分化，还能促进脑内各种神经营养因子分泌，减小脑缺血动物模型的缺血灶，促进慢性脑卒中模型缺失神经功能的长期恢复。 目的：观察粒细胞集落刺激因子对血管性痴呆大鼠海马神经细胞凋亡的作用。 方法：采用永久性双侧颈总动脉结扎法建立大鼠血管性痴呆模型，抽签法随机分为4组：实验组(皮下注射粒细胞集落刺激因子干预治疗)、对照组(注射生理盐水)、假手术组(仅行颈前正中切开，不结扎颈总动脉)。采用Morris水迷宫进行定向航行观察大鼠逃避潜伏期，评价大鼠空间学习记忆能力，TUNEL染色和图像分析大鼠海马神经细胞的凋亡。 结果与结论：对照组和实验组大鼠脑缺血后7 d，大鼠平均逃避潜伏期较假手术组明显延长(P < 0.01)，海马组织TUNEL阳性凋亡细胞较假手术组显著增高(P < 0.01)，随着时间的延长，14，28 d时大鼠学习记忆功能障碍逐渐加重，相应海马组织TUNEL阳性凋亡细胞逐渐增加。14，28 d时实验组大鼠平均逃避潜伏期比对照组明显缩短，海马组织TUNEL阳性凋亡细胞也较对照组显著减少。说明脑缺血后早期给予外源性粒细胞集落刺激因子有助于减少海马组织神经细胞的凋亡，改善大鼠学习记忆能力。     

Regional differences in rat brain lipids during global ischemia.

BACKGROUND AND PURPOSE: Membrane lipid degradation plays an important role in the pathogenesis of ischemic brain damage, but there is little information on changes in cerebrosides, sulfatides, and sphingomyelin. We studied regional changes in the quantities of these lipids during complete global brain ischemia in rats. METHODS: Nitrous oxide-anesthetized rats were subjected to ischemia by a high-pressure neck cuff and arterial hypotension for 0 (control), 3, 10, or 30 minutes (n = 5 at each time). Brain temperature was allowed to fall spontaneously during ischemia, and the brain was frozen in situ with liquid N2 without recirculation. The frontal cortex, hippocampus, and basal ganglia were dissected at -15 degrees C. The lipids were separated by column and high-performance thin-layer chromatography and quantified by charring and densitometry. RESULTS: Total lipid content was higher (p less than 0.01) in the hippocampus (72.6 +/- 2.8 mg/g wet wt, mean +/- SD) than in the frontal cortex and basal ganglia (57.7 +/- 2.1 and 62.6 +/- 1.5 mg/g wet wt, respectively). Ischemic changes occurred only in the frontal cortex, where total lipid content fell (p less than 0.01) by 11% after 30 minutes of ischemia because sulfatide and cerebroside contents fell by 44% and 38%, respectively. CONCLUSIONS: Despite a marked accumulation of free fatty acids during complete global brain ischemia in rats, the only detectable changes in brain lipids were in the amounts of cerebrosides and sulfatides in the frontal cortex.     

阿托伐他汀可增强血管性痴呆模型中大鼠海马CA1区发动蛋白1的表达

The current study examined a rat model of vascular dementia.The model rats exhibited obvious morphological and ultrastructural changes in neurons in the brain,and significantly reduced dynamin 1 expression in hippocampal CA1 region along with decreased learning and memory performance.Following atorvastatin treatment,the morphology and ultrastructure of cells in the model rat brain were significantly improved,dynamin 1 expression in hippocampal CA1 region was significantly enhanced,and learning and memory ability was significantly improved.The results demonstrated that impaired learning and memory abilities in vascular dementia model rats were closely correlated with decreased dynamin 1 expression.These findings indicate that atorvastatin can protect model rats against cognitive impairment by increasing dynamin 1 expression.     

Rhesus monkey neural stem cell transplantation promotes neural regeneration in rats with hippocampal lesions

Rhesus monkey neural stem cells are capable of differentiating into neurons and glial cells.Therefore,neural stem cell transplantation can be used to promote functional recovery of the nervous system.Rhesus monkey neural stem cells(1×105 cells/μL) were injected into bilateral hippocampi of rats with hippocampal lesions.Confocal laser scanning microscopy demonstrated that green fluorescent protein-labeled transplanted cells survived and grew well.Transplanted cells were detected at the lesion site,but also in the nerve fiber-rich region of the cerebral cortex and corpus callosum.Some transplanted cells differentiated into neurons and glial cells clustering along the ventricular wall,and integrated into the recipient brain.Behavioral tests revealed that spatial learning and memory ability improved,indicating that rhesus monkey neural stem cells noticeably improve spatial learning and memory abilities in rats with hippocampal lesions.     

卡因酸对大鼠学习记忆和P物质表达的影响

目的 :探讨卡因酸对大鼠学习记忆能力的影响 ,观察其基底前脑皮质 P物质表达的变化。方法 :大鼠腹腔注射卡因酸为实验组 ,注射磷酸缓冲生理盐水 (PBS)为对照组。用 Y迷宫测试大鼠学习记忆 ,用乙酰胆碱酯酶 (Ach E)化学染色检测神经元丢失情况 ,免疫组化检测 P物质表达水平的变化。结果 :实验组大鼠的学习记忆能力明显低于对照组 (P<0 .0 5 ) ,乙酰胆碱酯酶表达水平明显低于对照组 (P<0 .0 1) ,P物质表达水平明显高于对照组 (P<0 .0 1)。结论 :腹腔注射卡因酸可以损害大鼠的学习记忆能力 ,导致胆碱能神经元损害。过高浓度的 P物质可能参与卡因酸导致学习记忆受损的发病机制     

甲基维生素B12对拟血管性痴呆大鼠记忆功能及脑白质病理变化的影响

目的 观察甲基维生素B12对拟血管性痴呆大鼠记忆功能及脑白质病理变化的影响。方法 反复前脑缺血制备大鼠拟血管性痴呆模型，造模后甲基维生素B12治疗1周、2周、4周时Morris水迷宫检测大鼠学习记忆功能、LFB染色观察白质髓鞘变化、电镜下观察少突胶质细胞、髓鞘超微结构，并与假手术组及对照组对比。结果 治疗4周大鼠游迷宫时间明显短于对照组，造模2周、4周时LFB染色均可见白质髓鞘脱失，但治疗组明显较对照组轻。造模4周电镜下少突胶质细胞、髓鞘改变治疗组轻于对照组。结论 甲基维生素B12能改善拟血管性痴呆大鼠记忆功能，并能减轻脑白质病理变化。     

Impact of enriched-environment housing on brain-derived neurotrophic factor and on cognitive performance after a transient global ischemia

Environmental enrichment promotes structural and functional changes in the brain, including enhanced learning and memory performance in rodents. Transient global cerebral ischemia (15 min) causes specific damage to dorsal hippocampal area CA1 pyramidal cells of the rat concomitantly with cognitive deficits. Thus, we investigated if environmental enrichment can protect rats against the cognitive and neurological consequences of transient ischemia. We evaluated the impairment of learning and memory with three tasks: odour discrimination, object exploration and spatial learning. Contrary to expectation, we found that the enriched environment improved performances for both ischemic and sham rats in odour discrimination and object exploration tasks compared with standard condition housed rats. After exposure to an enriched environment, ischemic rats performed better in the water maze than those in the standard housing conditions. However, exposure to an enriched environment does not protect against actual loss of CA1 pyramidal cells. Brain-derived neurotrophic factor (BDNF) levels were increased in environmental enrichment animals compared to those housed in standard conditions. We conclude that environmental enrichment has positive effects that are independent of the effects of ischemic brain lesions.     

Homocysteine has anti-inflammatory properties in a hypercholesterolemic rat model in vivo

Inflammation is a hallmark in many neurodegenerative diseases like Alzheimer's disease or vascular dementia. Cholesterol and homocysteine are both vascular risk factors which have been associated with dementia, inflammation and blood-brain barrier dysfunction. In previous studies we found that hypercholesterolemia but not hyperhomocysteinemia induced inflammation in rats in vivo. The aim of the present study was to investigate the effect of a combined treatment of Sprague Dawley rats with cholesterol and homocysteine for 5 months on spatial learning and memory, blood-brain barrier integrity and inflammation. Cholesterol treated rats showed severe learning deficits, while rats treated with cholesterol and homocysteine (Mix) counteracted the cholesterol-induced inflammation and partly the cortical blood-brain barrier disruptions, although cognition was still impaired. To study the potential protective effect of homocysteine, inflammation was induced in organotypic rat brain cortex slices and primary microglial cells by treatment with different inflammatory stimuli (e.g. lipopolysaccharide or tissue plasminogen activator). Tissue plasminogen activator-induced inflammation was counteracted by homocysteine. In conclusion, our data demonstrate that homocysteine significantly ameliorates cholesterol-induced inflammation and blood-brain barrier disruption but not the memory impairment, possibly involving a tissue plasminogen activator-related mechanism.     

高压氧并雌二醇治疗老年痴呆鼠学习记忆障碍的实验观察

目的探讨高压氧与雌二醇对老年痴呆大鼠学习记忆功能的影响。方法用D-半乳糖(150mg kg)和亚硝酸钠(90mg/kg)联合制作老年痴呆SD大鼠模型,用单纯高压氧、单纯雌二醇、联合高压氧雌二醇治疗,用Marri水迷宫试验、跳台试验评定模型是否成功及治疗前后成绩的差异。结果40只AD模型制作成功,治疗前后三组在Marr1迷宫、跳台试验中成绩明显提高(P<0.05);单纯雌二醇及高压氧组在测试中成绩比高压氧联合雌二醇组差(P>0.05);而两组间无显著差异(P<0.05);但所有模型组成绩差于正常对照治疗组(P<0.05)。结论高压氧联合雌二醇对老年痴呆大鼠学习记忆功能有明显改善作用。