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1、1血管内皮生长因子在脑缺血耐受大鼠中的表达作者：王国峰 沈娜娜 王静云 陈卫 赵仁亮【摘要 】 目的 检测局灶性脑缺血预处理诱导大鼠脑缺血耐受模型再灌注不同时间窗血管内皮生长因子(VEGF)的表达，探讨其在脑缺血耐受中的作用。方法 将 55 只 Wistar 大鼠随机分成假手术对照组（SS+SS ，5 只） 、假手术再缺血组（SS+MCAO，25 只） 、缺血预处理再缺血组（IP+MCAO，25 只） ，后两组再随机分成5 个亚组。线栓法阻塞大脑中动脉(MCAO)建立局灶性缺血预处理模型（缺血预处理 10 min） ，分别在缺血预处理后1、3 、7 、 14、21 d 进行再次缺血 2 h 再
2、灌注 22 h，然后取脑检查。应用苏木精 伊红染色观察脑组织病理变化并测定脑梗死体积，观察神经行为缺损,免疫组化法检测 VEGF 蛋白表达。结果 IP+MCAO组 1、3、7 d 亚组与 SS+MCAO 组相应亚组比较，神经行为缺损评分明显降低,梗死体积明显减小,VEGF 表达明显增高，差异均有显著性（t=2.35711.479，P0.05） 。结论 缺血预处理诱导了脑缺血耐受，预缺血诱导的 VEGF 表达增加在脑缺血耐受中发挥重要作用。 2【关键词】 血管内皮生长因子 A；缺血预处理；脑缺血；大鼠ABSTRACT Objective To investigate the expression
3、 of vascular endothelial growth factor (VEGF) at different time points after reperfusion in a cerebral ischemiatolerant rat model induced by focal ischemia preconditioning, and study the significance of VEGF in cerebral ischemia tolerance. Methods Fiftyfive healthy Wistar rats were randomized to thr
4、ee groups: the sham operation group (SS+SS，n=5), the sham opertation and subsequent middle cerebral artery occlusion (MCAO) group (SS+MCAO,n=25), and the ischemia preconditioning and subsequent MCAO group (IP+MCAO,n=25). The latter two groups were further divided into five subgroups. For ischemia pr
5、econditioning, the rats were performed MCAO with filament ligation for 10 min. On the 1st, 3rd, 7th, 14th and 21st day after ischemia preconditioning, the rats were given the second MCAO for 2 h followed by 22 h reperfusion. Brain tissues were biopsied and tissue sections stained with hematoxylin an
6、d eosin (HE) for histological study and determination of infarction volume. The models were evaluated with neurological deficit score. The expression of VEGF was determined by 3immunohistochemical staining. Results Compared with the corresponding subgroups of SS+MCAO group, the neurologic scores wer
7、e significantly reduced, the volume of cerebral infarction was significantly decreased and the expression of VEGF significantly increased in the 1st, 3rdand 7stday subgroups of IP+MCAO group (t=2.357-11.479，P0.05） ；IP+MCAO 组以 3 d 亚组梗死体积减小最8为明显(F=25.745,q=4.3739.859,P0.05)，并且 1、3 、7 d亚组梗死体积较 SS+MCAO
8、组相应亚组明显减小，分别减小22.3%、36.1%、25.9%，差异有显著意义（t=5.88010.801,P0.01） 。见表 2。 表 2 各组大鼠脑组织梗死体积的百分比及其比较（略）2.3 各组不同时间 VEGF 表达的比较对照组大鼠未见有明显 VEGF 阳性表达。SS+MCAO 组与IP+MCAO 组可见较多的 VEGF 蛋白阳性表达细胞，主要分布于缺血灶及周围的神经胶质细胞、神经元及微血管内皮细胞，胞浆棕黄色，着色明显。其中，VEGF 在 IP 后 1 d 即明显升高，持续至 7 d（F=28.878、33.815，q=5.70913.567，P0.05）,明显高于SS+MCAO 组的相应亚组（ t=2.71811.479,P0.05 ） ，高峰出现在 IP 后 3 d。见表
