阿替普酶对急性脑梗死大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白表达的影响

摘要

目的:探讨阿替普酶对急性脑梗死大鼠溶栓后血管内皮细胞中闭合蛋白1(Claudin-1)和闭合蛋白5(Claudin-5)表达的影响及保护作用机制,为阿替普酶的临床应用提供依据.方法:建立大鼠急性大脑中动脉栓塞模型.54只SD大鼠随机分为假手术组、模型组和阿替普酶溶栓组,每组18只.透射电子显微镜下观察大鼠脑内皮细胞超微结构,荧光免疫组织化学法和Western blotting法检测大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白的表达水平.结果:透射电子显微镜检测,模型组大鼠缺血区域脑体积明显增大,内皮细胞肿胀,部分皮质与周围脑组织界限明显,基膜厚薄均匀,紧密连接结构非常松散、出现断裂和消失;阿替普酶溶栓组大鼠脑梗死区域毛细血管内皮细胞肿胀明显减轻,基膜厚薄不均匀改善,脑毛细血管内皮细胞、内皮细胞之间大部分紧密连接结构断裂情况消失,无紧密连接结构消失.荧光免疫组织化学检测,与模型组比较,阿替普酶溶栓组大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白的表达有明显改善.Western blotting检测,与假手术组比较,模型组大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白表达水平明显减少(P<0.01);与模型组比较,不同时间点阿替普酶溶栓组大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白表达水平均升高(P<0.01).结论:阿替普酶对急性脑梗死大鼠大脑内皮细胞的结构有改善作用,其作用机制可能与阿替普酶能降低大鼠血管内皮细胞中Claudin-1和Claudin-5蛋白表达水平有关.%Objective:To investigate the effect of alteplase on the expressions of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells after thrombolysis in the rats with acute cerebral infarction and its mechanism,and to provide experimental evidence for its clinical application. Methods: The models of acute thrombosis of middle cerebral artery of the rats were established.Fifty-four SD rats were randomly divided into sham operation group,model group and alteplase group (n= 18).The ultrastructure of brain endothelial cells of the rats was observed under transmission electron microscope.The expression levels of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells of the rats were detected by immunoflurorescence and Western blotting methods.Results:The transmission electron microscope results showed that the brain volume in the ischemic area of the rats in model group was significantly increased and the endothelial cells were swollen,some of the cortical and surrounding brain tissues had obvious boundaries,and the thickness of the basement membrane was uniform and the tightly connected structure was very loose and disappeared;the swelling condition of the capillary endothelial cells in infarcted area of the rats in alteplase group was significantly reduced and the thickness of the basement membrane was improved,and most of the tightly connected structures between the brain capillary endothelial cells and the endothelial cells were loose and the fracture was lost and the structure disappeared.The immunofluorescence results showed that the expressions of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells of the rats in alteplase group were significantly improved compared with model group. The Western blotting results showed the expression levels of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells of the rats in model group were significantly decreased compared with sham operation group (P < 0.01 ); compared with model group, the expression levels of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells of the rats in alteplase group at different time points were increased (P < 0.01 ). Conclusion: Alteplase can improve the structure of brain endothelial cells in the rats with acute cerebral infarction,and the mechanism may be related to decreasing the expressions of Claudin-1 and Claudin-5 proteins in the vascular endothelial cells of the rats induced by alteplase.