大鼠局灶性脑缺血再灌注小动脉血管平滑肌细胞表型转化的实验研究

目的　观察大脑中动脉缺血再灌注大鼠模型小动脉血管平滑肌细胞 (VSMC)中两种血管舒缩功能相关蛋白(α 平滑肌肌动蛋白和细丝蛋白 )的免疫组织化学表达变化 ,以期了解脑小动脉病变中VSMC的表型转化及细丝蛋白在表型转化中的意义 ,指导临床小动脉硬化型脑卒中的准确防治。方法　缺血再灌注组依照再灌注时间的不同分为 2、6、12、2 4h、3d及 7d共 6个亚组 ,另设正常对照组及大脑中动脉持续缺血组。按时相点取材 ,免疫组织化学染色 ,图像分析。结果　α 平滑肌肌动蛋白在再灌注 6h后表达明显下降 ,在 2 4h时表达最低 ,在 3d时表达有所升高 ,7d时表达最高 ;细丝蛋白缺血 2h后表达稍有下降 ,以 12h时的表达最低 ,2 4h时表达升高 ,在 3d时表达最高。结论　再灌注损伤可引起小动脉VSMC表型的变化 ;细丝蛋白也可作为VSMC表型变化的指标之一 ,与α 平滑肌肌动蛋白相比意义更大 ;细丝蛋白和α 平滑肌肌动蛋白可能在再灌注中起下调炎症反应及保护细胞的作用

Experimental studies of phenotype switch of arteriolar VSMC after cerebral focal ischemia-reperfusion in rats

Objective To observe expression of α SM Actin and filamin(FLN) in the arteriolar smooth muscle cells after cerebral ischemia reperfusion to find out the significance of phenotype switch in ischemic stroke and the role of filamin in phenotype switching.Methods Middle cerebral artery occlusion reperfusion(MCAO R) model was established after the rats were divided into sham operation group,ischemia reperfusion group and continuous ischemia group.The ischemia reperfusion group was divided into six subgroups according to different time of reperfusion from 2h to 7d.Immunohistochemical staining method and color image analysis were used to observe the expression.Results Expression of actin decreased after 6 h of reperfusion,and in 24 h group the expression was the lowest.In 3d and 7 d groups,expression of actin increased.Expression of FLN began to decrease after 2h of reperfusion,and in 12 h group the expression was much lower than that in other groups.In 24 h group the expression increased and the expression in 3d group was the highest.Conclusions Ischemia reperfusion can cause phenotype switch of VSMC.FLN can be another most important sign of phenotype switch of VSMC and maybe a better sign than α SM Actin.The expression results hint that the two proteins may relieve inflammatory reaction and protect cells.