【摘要】 目的:探讨Ephrin-B2在大鼠脑缺血再灌注后脑组织中的表达情况以及对血管新生的调节作用。方法:雄性SD大鼠随机分为正常对照组、假手术组及缺血再灌注组,后者又分为1,3,7,14,28 d亚组,线栓法制备局灶性大脑中动脉缺血再灌注模型;改良神经功能评分(modified neurological severity scores,mNSS)法对各时间点模型进行评分;Western印迹及荧光定量PCR检测缺血脑组织中Ephrin-B2的表达;以免疫荧光双标法定位Ephrin-B2表达的细胞类型;以CD31+内皮细胞计数缺血半暗带中微血管密度(microvessel density,MVD)。结果:缺血半暗区MVD从缺血再灌注后第3天起较假手术组开始增加,第14天最高(P<0.01),第28天有所回落;再灌注7 d亚组的神经功能评分较1 d及3 d亚组增加,14 d开始下降;Ephrin-B2在血管内皮、血管周围、神经元细胞膜及星形胶质细胞中均有显著表达;Ephrin-B2蛋白及mRNA水平从再灌注第3天开始显著增加,到第7天及14天(P<0.01)表达水平最高。结论:脑缺血再灌注可诱导Ephrin-B2表达升高,并呈动态变化趋势,Ephrin-B2参与了脑缺血后血管新生的调控过程,并促进脑缺血后血管新生,从而促进神经功能恢复。更多还原

【Abstract】 Objective: To explore the expression proi le of Ephrin-B2 in the ischemic penumbra at er transient focal cerebral ischemia in rats, and to clarify the mechanism of Ephrin-B2 triggering angiogenesis. Methods: Sprague-Dawley rats were randomly divided into a normal group, a sham operation group and ischemic-reperfusion 1, 3, 7, 14, and 28 d groups. Suture-occluded method was used to establish the focal middle cerebral artery occlusion model and the ischemic brain was reperfused 2 h at er the occlusion. Western blot and quantitative real-time reverse-transcription polymerase chain reaction were used to detect the dynamic expression profile of Ephrin-B2 in the penumbra cortex. Double immunofluorescence was used to speculate the location and the co-expression of Ephrin-B2 in blood vessels, neurons and astrocytes. Microvessel density was quantified by the number of CD31+ cells. Rats were subjected to neurologic functional tests by modii ed neurological severity scores(mNSS) before sacrii ce. Results: Compared with the sham group, Ephrin-B2 protein and mRNA level of the penumbra cortex in the ischemic group increased 3 days(P<0.05) after the reperfusion, peaked at day 7 and 14(P<0.01), and declined at day 28. Double immunol uorescence indicated that Ehprin-b2 was expressed in the neurons, blood vessels and astrocytes; mNSS peaked at day 7, and gradually declined at day 14. h e microvessel density of penumbra cortex in the ischemic group increased 3 days(P<0.05) at er the reperfusion, peaked at day 14(P<0.01), and gradually declined at 48 h. Conclusion: Cerebral ischemia reperfusion induces the over-expression of Ephrin-B2, with a dynamic trend, suggesting that Ehprin-b2 may improve post-stroke functional recovery by enhancing angiogenesis and neurogenesis.更多还原