水通道蛋白4在大鼠脑缺血再灌注损伤中的作用

目的研究水通道蛋白4(AQP4)在缺血再灌注损伤大鼠脑内表达及作用。方法以大脑中动脉线栓法建立大鼠缺血再灌注模型,采用干湿法测定模型的脑组织含水量及伊文氏蓝含量;免疫蛋白印记(WesternBlot)技术分析在缺血再灌注不同时程脑内AQP4的表达情况,以及AQP4与脑含水量和伊文氏蓝水平的相关性,并与对照组比较。结果与对照组相比,实验组大鼠脑组织含水量及伊文氏蓝水平在缺血再灌注后不同时间点明显高于对照组(P<0.05～0.01);AQP4蛋白表达明显增高(均P<0.05),并随着缺血再灌时间的延长,其表达量亦逐渐增加,在再灌后24～48h达到高峰。缺血再灌注后AQP4脑内的表达与脑组织含水量及伊文氏蓝水平呈正相关(r=0.38、r=0.45,均P<0.05)。结论AQP4的高表达参与了脑缺血再灌注后继发的血脑屏障的开放和脑水肿的发生,是脑水肿产生的重要分子基础。

Role of aquaporin-4 on cerebral ischemia/reperfusion injury in rats

Objective To investgate the role of aquaporin-4(AQP4) in secondary cerebral edema after ischemia/reperfusion injury in rats.Methods When the models of reversible middle cerebral artery occlusion were established, the alterations of cerebral edema and BBB were evaluated by measuring water and Eval's Blue (EB) contents of cerebral tissue, and the expression of AQP4 in brain was observed by Western Blot at different time point after reperfusion. At last, the correlation between expression of AQP4 and water and EB contents of cerebral tissue were analysed.Results There were found that water and EB contents of cerebral tissue in rat models significantly higher than those of control group at different time point after ischemia/reperfusion ( P<0.05~0.01). At the same time, compared with control group, AQP4 expression in cerebral edema group showed obviously statistical increasing(all P<0.05). The expression of AQP4 increased gradually after ischemia/reperfusion.It reached the peak between 24 h and 48 h after reperfusion. The positive correlation was found between expression of AQP4 and water and EB contents of cerebral tissue( r=0.38, r=0.45, all P<0.05).Conclusions High expression of AQP4 may involve in secondary cerebral edema and BBB opening after cerebral ischemia/reperfusion, and it is an important molecular mechanism of cerebral edema formation.