大鼠脑缺血时中枢单胺类神经递质的研究

大鼠脑缺血时中枢单胺类神经递质的研究周陆生，梁熙南，吴祥，魏琦近年来对脑血管病的神经生化研究发现，中枢单胺类神经递质的代谢异常对脑组织的损伤及发展有密切的影响，认为单胺类神经递质在缺血性脑损伤的病理生理过程中起重要作用。但由于各种原因，至今对它们代谢...     

脑缺血纹状体细胞外液单胺类介质及其代谢物的微透析研究

目的观察脑缺血再灌注时鼠脑纹状体区细胞外液（ＥＣＦ）多巴胺（ＤＡ）、去甲肾上腺素（ＮＥ）、５－羟色胺（５－ＨＴ）及其代谢产物高香草酸（ＨＶＡ）和５－羟吲哚乙酸（５－ＨＩＡＡ）的动态变化。方法采用脑内微透析技术，用高压液相色谱测定了前脑缺血３０ｍｉｎ、再灌注１２０ｍｉｎ时ＥＣＦＤＡ、ＮＥ和５－ＨＴ的变化。结果脑缺血１０ｍｉｎ时ＥＣＦＤＡ、ＮＥ迅速升高为缺血前的２８２和９１４倍，持续整个缺血期，再灌注后迅速下降达缺血前水平。脑缺血期ＨＶＡ、５－ＨＩＡＡ迅速下降，在缺血３０ｍｉｎ时达缺血前的４５％和５２％，再灌注后升高并在再灌注后６０ｍｉｎ，９０ｍｉｎ达缺血前的１５０％、１１３％。结论单胺类介质代谢紊乱参与了缺血性神经元损害     

巴曲酶对脑缺血再灌注细胞外液单胺类及其代谢产物的影响 …

目的 巴曲酶对脑缺血再灌流损伤的保护机理。方法 采用脑内微透析技术结合高灵敏度的高压液相色谱－电化学检测手段（ＨＰＬＣ－ＥＤ），测定前脑缺血３０ｍｉｎ再灌注１２０ｍｉｎ时的纹状体细胞外液（ＥＣＦ）的ＤＡ、５－ＨＴ和ＮＥ及其代谢产物（５－ＨＩＡＡ）和ＨＶＡ的变化和巴曲酶的影响。结果 显示脑缺血时，ＥＣＦ ＤＡ、ＮＥ及５－ＨＴ明显升高，巴曲酶能显著地降低脑缺血时ＥＣＦ ＤＡ及再灌注时ＥＣＦ ＨＶＡ和５     

全脑缺血后海马区单胺类神经递质的变化

目的观察全脑缺血后大鼠海马区单胺类神经递质的变化规律,探讨其在缺血后迟发性神经元死亡中的作用。方法建立大鼠全脑缺血再灌注模型,观察全脑缺血再灌注后酪氨酸羟化酶(TH)、多巴胺-β-羟化酶(DβH)的表达并对海马区去甲肾上腺素(NE)、肾上腺素、多巴胺、5-羟色胺(5-HT)和单胺类神经递质代谢产物高香草酸(HVA)、5-羟吲哚乙酸(5-H IAA)的含量进行测定。结果对照组TH及DβH呈阴性表达。全脑缺血再灌注后1 d,3 d缺血组海马CA1区神经元TH及DβH表达阴性。5 d后神经元TH及DβH呈阳性表达;全脑缺血再灌注后6 h,缺血组海马区单胺类神经递质含量显著上升,NE、肾上腺素、多巴胺及5-HT分别为对照组的232.5%、347.3%、336.1%和210.1%,1 d后开始回落,3 d已明显低于对照组,5 d后又有回升并接近对照组;缺血组,海马区单胺类神经递质的代谢产物HVA、5-H IAA含量于全脑缺血再灌注后6 h开始上升,1 d依然保持较高的水平,至3 d回落,5 d接近对照组。结论全脑缺血再灌注后早期海马区单胺类神经递质含量显著上升;单胺类神经递质含量显著上升可能是导致迟发性神经元死亡的主要因素之一。     

巴曲酶对脑缺血再灌注细胞外液单胺类及其代谢产物的影响——微透析研究

目的巴曲酶对脑缺血再灌流损伤的保护机理。方法采用脑内微透析技术结合高灵敏度的高压液相色谱－电化学检测手段（ＨＰＬＣ－ＥＤ），测定前脑缺血３０ｍｉｎ再灌注１２０ｍｉｎ时的纹状体细胞外液（ＥＣＦ）的ＤＡ、５－ＨＴ和ＮＥ及其代谢产物（５－ＨＩＡＡ）和ＨＶＡ的变化和巴曲酶的影响。结果显示脑缺血时，ＥＣＦＤＡ、ＮＥ及５－ＨＴ明显升高，巴曲酶能显著地降低脑缺血时ＥＣＦＤＡ及再灌注时ＥＣＦＨＶＡ和５－ＨＩＡＡ的水平。结论巴曲酶影响单胺神经递质是对脑缺血再灌注损伤起保护作用的机理之一     

脑缺血时脑单胺类神经介质的动态变化

用萤光分光光度法测定蒙古沙土鼠左CCA结扎后脑3种单胺类递质的动态变化,经与假手术和空白对照组比较,证明缺血后0.5、3及24小时的脑半球的NE、5HT及DA含量均显著下降,前两种以术后3小时最低,此时非缺血侧的NE含量亦下降;卒中症状积分又与脑单胺含量呈负相关。认为缺血性卒中症状的发生和发展与脑单胺类递质含量下降有关。     

脑缺血再灌注肾脏损伤老龄大鼠的单胺类神经递质和神经肽的变化意义

目的：从多巴胺(DA)、去甲肾上腺素(NE)、肾上腺素(E)、内皮素(ET)和降钙素基因相关肽(CGRP)的变化方面揭示老龄大鼠脑缺血再灌注肾脏损伤机制。方法：青年(5月龄)和老龄(20月龄以上)大鼠均分为模型组和正常对照组，观察大鼠全脑缺血30min再灌注60min后肾脏组织形态和肌酐(Cr)、尿素氮(Bun)、DA、NE、E、ET、CGRP含量的变化。结果青年和老龄模型组大鼠肾脏组织形态和功能均出现明显的病理改变，交感-肾上腺系统兴奋性增强，老龄模型组较青年模型组严重。青年对照组血浆中CGRP高于青年模型组和老龄对照组。老龄模型组血中ET高于老龄对照组和青年模型组。结论：大鼠脑缺血再灌注肾脏损伤与交感-肾上腺系统兴奋性增强以及CGRP与ET的平衡失调有关，由于增龄的变化使老龄大鼠脑缺血再灌注肾脏损伤程度和这些病理变化尤为明显并具有一定特点。     

单胺类神经递质和神经肽Y在老龄大鼠脑缺血再灌注心脏组织损伤中的意义

目的 从多巴胺（DA）、去甲肾上腺素（NE）、肾上腺素（E）、神经肽Y（NPY）方面揭示脑缺血心肌损伤的机制。方法 观察青年（5－6月龄）和老龄（20月龄以上）大鼠全脑缺血心肌损伤乳酸脱氢酶（LDH）、肌酸磷酸激酶（CPK）活性及NPY、DA、NE、E的含量。结果 青年模型组血清中CPK和LDH水平明显高于青年对照组和老龄模型组，老龄模型组高于老龄对照组。青年模型组和老龄模型组血中NE分别高于青年和老龄对照组；老龄模型组血中NE、E水平和下丘脑NE水平高于青年模型组，老龄模型组下丘脑中NE和E水平低于老龄对照组。脑组织中NPY老龄对照组低于青年对照组和老龄模型组。结论 在鼠脑缺血再灌注心肌损伤与交感－肾上腺系统兴奋性增强有关，老龄大鼠尤为明显。     

The effect of age on expression of endogenous plasminogen activators after focal cerebral ischemia in mice

We measured urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen activator (t-PA) activity in the brain of 2–3 month old and 6–8 month old mice subjected to 4 h of middle cerebral artery (MCA) occlusion. t-PA activity was present in all non-ischemic and ischemic young mouse brain. In contrast, t-PA activity was present in 46.7% of non-ischemic middle aged mouse brain and in 44.4% of ischemic middle aged mouse brain. u-PA activity was present in all young and middle aged non-ischemic brains.     

大鼠脑缺血后胼胝体少突胶质细胞变化的特征

目的 观察脑缺血大鼠胼胝体少突胶质谱系细胞的动态变化规律.方法 采用4-VO脑缺血模型,随机分为2d、4d、7d、14d和28d 5个时间点及假手术组,每组8只;用组织芯片免疫组织化学检测胼胝体A2B5、O4、CNPase蛋白表达变化.结果 (1)CNPase阳性细胞于脑缺血后有不同程度减少,2d即明显减少,7d时减少到最低,14d时回升,28d时恢复至假手术组水平;与假手术组比较,脑缺血后2d、4d、7d有显著差异(P＜0.05).(2)O4阳性细胞数于脑缺血后2d时显著减少,4d时回升,28d时恢复至假手术组水平;与假手术组比较,2d、4d有显著差异(P＜0.05).(3)A2B5阳性细胞于脑缺血后随着再灌注时间延长而增加,2d时即已增多,持续至28d时达到高峰;与假手术组比较,7d、14d、28d有显著差异(P＜0.05).结论 脑缺血后OPC反应性增生,未成熟和成熟OLG减少,以未成熟OLG为著;提示未成熟OLG对缺血有易损性,而OPC有耐受性.     

Behavioral effects after systemic injection of opiate peptides

(1) Behavioral effects after systemic injection of opiate peptides have now been demonstrated across a wide range of behaviors in subjects ranging from goldfish to humans. (2) There is evidence that behavioral effects of brain opiates can occur independently of the narcotic effects. (3) Dose-response curves for enkephalin and endorphin usually assume an inverted U-shaped function, with 100 μg/kg as the apogee. (4) Use of the peripheral route for administration of opiate peptides has, therefore, had important theoretical and practical implications.     

大鼠脑缺血再灌注诱导自体神经干细胞原位增殖的研究

目的研究缺血性脑损伤对内源性神经干细胞增殖、迁移的影响。方法参照Pulsinelli-Brierley法制作短暂性全脑缺血动物模型,全脑缺血10min后再灌注,采用SABC免疫组化染色显示5'-溴脱氧尿嘧啶(BrdU)阳性细胞和神经巢蛋白(Nestin)阳性细胞,光镜下观察并统计分析脑缺血损伤后内源性神经干细胞增殖、迁移的变化过程。结果脑缺血再灌流24h后,海马、齿状回和室管膜下区的BrdU阳性细胞和Nestin阳性细胞增多,7～10d达到高峰,术后20d仍有表达;在室管膜下区,BrdU阳性细胞和Nestin阳性细胞有向皮质、海马迁移的现象。结论①成年大鼠全脑缺血后7～10d,内源性神经干细胞的增殖达到高峰。②增殖的内源性神经干细胞存在由增殖区向靶区迁移的现象。     

内源性VEGF表达对缺血性脑损伤后成年大鼠海马齿状回神经发生影响的实验研究

2-EGFP-U6-shRNA(VEGF)立体定向给药大鼠缺血性脑损伤后24h和6d时缺血性脑损伤诱导的大鼠海马VEGF mRNA表达水平反应性升高可被抑制(P<0.05),海马内源性VEGF mRNA表达水平的降低可显著下调缺血性脑损伤后齿状回神经前体细胞增殖水平.结论 内源性VEGF基因表达可能是缺血性脑损伤后齿状回神经前体细胞增殖的一个重要启动信号.VEGF是耦联缺血性脑损伤和齿状回神经发生的关键分子.     

Changes in endogenous antioxidant enzymes during cerebral ischemia and reperfusion

OBJECTIVE: The purpose of this study was to investigate the role of catalase (Cat), glutathione S transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx) in cerebral ischemia induced by occluding the carotid arteries of male Wistar rats. METHODS: The activities of the antioxidant enzymes Cat, GR, GPx and GST were measured in the cerebral cortex, cerebellum and hippocampus regions after varying periods of ischemia and reperfusion. RESULTS: In all ischemia/reperfusion groups (0, 1 and 24 hours of reperfusion), the enzyme activities were found to be altered when compared to the sham-operated controls. The alterations were significant (p< or =0.05) in all reperfusion groups, particularly after 1 hour of reperfusion in all brain regions; however, maximum alterations were detected in the more vulnerable hippocampus. DISCUSSION: Our findings indicate that the endogenous antioxidant enzymes are activated as soon as 1 hour after ischemia. In spite of significant up-regulation of these enzymes, a large number of neurons in selectively vulnerable regions of hippocampus undergo neurodegeneration. These biochemical changes suggest that vulnerability to oxidative stress in brain is region-specific. However, these changes which are adaptive or compromise the capacity of the brain to deal with the oxidative stress that could lead to neurodegeneration remains to be understood.     

Angiogenesis after cerebral ischemia

Though the vascular system of the adult brain is extremely stable under normal baseline conditions, endothelial cells start to proliferate in response to brain ischemia. The induction of angiogenesis, primarily in the ischemic boundary zone, enhances oxygen and nutrient supply to the affected tissue. Additionally, the generation of new blood vessels facilitates highly coupled neurorestorative processes including neurogenesis and synaptogenesis which in turn lead to improved functional recovery. To take advantage of angiogenesis as a therapeutic concept for stroke treatment, the knowledge of the precise molecular mechanisms is mandatory. Especially, since a couple of growth factors involved in post-ischemic angiogenesis may have detrimental adverse effects in the brain by increasing vascular permeability. This article summarizes the knowledge of molecular mechanisms of angiogenesis following cerebral ischemia. Finally, experimental pharmacological and cellular approaches to stimulate and enhance post-ischemic angiogenesis are discussed.     

缺血脑组织内皮素含量变化的实验研究

为探讨内皮素含量变化是否为缺血神经元损伤的危险因素及Ca~(2+)拮抗剂氟桂嗪对脑缺血的保护作用,采用放射免疫分析法,我们测定兔大脑中动脉阻断48小时后缺血区脑组织内皮素含量变化及氟桂嗪对其变化的影响。结果显示,缺血48小时后梗塞区脑组织内皮素含量明显升高(P<0.01),为对照组的10倍,而氟桂嗪能明显降低缺血区脑组织水、内皮素含量(P<0.05)。上述结果提示:缺血脑组织内皮素含量升高是导致缺血神经元损伤的重要因素,氟桂嗪对脑缺血有保护作用。