亚低温对脑梗死后AQP4表达及血脑屏障通透性的影响

目的 观察脑梗死后亚低温干预对大鼠水通道蛋白4(aquaporin 4,AQP4)表达及血脑屏障(blood brain-barrier,BBB)通透性的影响,探讨亚低温对缺血性脑水肿的作用机制.方法 线栓法制造大鼠局灶性脑缺血模型,同时给予亚低温治疗.用免疫组织化学方法检测AQP4和IgG的表达.用干湿重法检测脑水含量.结果 再灌注损伤后脑内AQP4蛋白水平迅速降低,至再灌注后12h达最低水平,至再灌注7d时接近正常水平.亚低温组AQP4、IgG表达及脑水含量均明显低于常温组.结论 ①脑梗死后,AQP4表达水平迅速下降,可能是机体的一种保护性反应;②亚低温能有效抑制脑梗死后AQP4的表达和血脑屏障通透性的增加.

Effects of mild hypothermia on aquaporin 4 expression and blood brain-barrier permeability in infarcted cerebral tissues

Objective To study the effects of mild hypothermia on aquaporin 4 (AQP4) expression and blood brain-barrier permeability in rat focal infarcted cerebral tissues,and investigate the mechanisms of mild hypothermia on ischemic brain edema.Methods The focal cerebral ischemia-reperfusion SD rat models were made by thread embolism in middle cerebral artery. Some of these rats were treated with mild hypothermia. The expression of AQP4 and IgG were observed by immunohistochemical technique, and the water content of brain was evaluated by wet-dry weight method. Results The level of AQP4 expressions in the rats decreased quickly after focal cerebral ischemia and reperfusion.The lowest point was 12h after reperfusion.The expressions of AQP4 went back to normal at Day 7. In the mild hypothermia group, the AQP4 and IgG expression levels and the water contents at every time point were obviously lower than those in the normal temprature group (P < 0.05). Conclusion (1)The decreased AQP4 expressions after ischemia-reperfusion are probably protective responses. (2)Mild hypothermia may relieve cerebral edema after cerebral infarct since it can inhibit AQP4 expressions and increase blood brain-barrier permeability.