【摘要】 目的探讨绿茶多酚对局灶性脑缺血大鼠血脑屏障的通透性及紧密连接蛋白occludin、claudin-5和蛋白激酶PKCα表达的影响。方法采用线栓法制作大鼠局灶性脑缺血模型,伊文思蓝法检测血脑屏障通透性的变化,免疫组化方法检测缺血脑组织occludin、claudin-5的表达,western blot方法检测脑缺血组织PKCα蛋白的表达。结果大鼠局灶性脑缺血60min、120min的脑组织血脑屏障通透性显著增加,同时点的脑组织BBB紧密连接开放;而绿茶多酚显著降低血脑屏障的通透性(P<0.01),使BBB紧密连接处于关闭状态。大鼠局灶性脑缺血60min及120min脑组织紧密连接相关蛋白occludin、claudin-5的蛋白表达水平显著降低,绿茶多酚显著上调这些蛋白表达水平(P<0.01)。大鼠局灶性脑缺血30min至120min脑组织中PKCα的蛋白表达水平显著升高,绿茶多酚显著降低PKCα蛋白的表达水平(P<0.01)。结论绿茶多酚降低缺血大鼠脑组织血脑屏障通透性可能与上调紧密连接蛋白occludin、claudin-5的表达及下调蛋白激酶PKCα的表达有关。更多还原

【Abstract】 Objective To evaluate the effect and possible mechanism of Green tee polyphenol on the bloodbrain barrier(BBB) permeability in cerebral ischemia rats.Methods he focal cerebral ischemia model of middle cerebral artery occlusion(MCAO) was performed by intraluminal suture.BBB permeability was quantitatively determined by Evans blue assay.The expressions of Clsudin-5 and occludin in ischemic brain tissues were detected by immunohistochemistry and Western blot,PKC α levels were determined by western blot.Results In focal cerebral ischemia rats at ischemia 60 min and ischemia 120 min,the permeability of BBB increased significantly,tight junction(TJ) of the brain tissue opened,but Green tea polyphenols significantly decreased the permeability of BBB and closed TJ of the brain tissue.Ischemia decreased significantly the expression levels of occluding and claudin-5,green tea polyphenol significantly increased the expression levels of occluding and claudin-5.Ischemia significantly increased the expression level of PKC α’ protein,green tea polyphenols significantly reduced the expression level of PKC α.Conclusion The decreased permeability of brain ischemic BBB by Green tea polyphenols might be related to the increased expression of occludin and claudin-5 and the decresed expression of PKC α.更多还原