亚低温对大鼠局灶性脑缺血后神经细胞凋亡及Bcl-X_L、Bcl-Xs、HSP70mRNA表达的影响

Effects of mild hypothermia on the apoptosis of neurocyte and the expression of Bcl-X_L、Bcl-Xs and HSP70 mRNA after focal cerebral ischemia in rats

目的观察亚低温对大鼠局灶性脑缺血后神经细胞凋亡及Bcl-XL、Bcl-Xs和HSP70mRNA表达的影响。方法成年健康Wistar大鼠140只,随机分为假手术组、缺血再灌注组(H0组)、缺血后即刻亚低温组(H1组)和缺血再灌注后亚低温组(H2组),应用线栓法建立大脑中动脉闭塞(MCAO)再灌注模型。利用冰袋行亚低温治疗,使大鼠体温下降。采用原位末端标记法检测脑组织细胞凋亡表达的变化,采用原位杂交方法检测脑组织Bcl-XL、Bcl-Xs和HSP70mRNA表达的变化。结果亚低温治疗组(H1及H2组)凋亡阳性细胞出现高峰时间延迟,且数量明显减少,Bcl-XL与Bcl-Xs之比显著高于H0组;H1组各时间点HSP70的表达明显高于H2组。结论亚低温具有脑保护作用,脑缺血后即刻亚低温的作用优于脑缺血再灌注后亚低温治疗。

Objective To observe the effects of mild hypothermia on the apoptosis of neurocyte and the expression of Bcl-X_L, Bcl-Xs and HSP70 mRNA after focal cerebral ischemia in rats. Methods One hundred and forty adult rats were randomly divided into 4 groups: a sham-operated group (SO group), a cerebral ischemia-reperfusion group (CIR group), a cerebral ischemia plus hypothermia group (CIH group) and a cerebral ischemia-reperfusion plus hypothermia group (CIRH group). Following establishment of a permanent middle cerebral artery occlusion (MACO) model in rats by using Zea-Longas method, the changes of apoptosis of neurocyte were measured with TUNEL assay, and the changes of the expression of Bcl-X_L, Bcl-Xs, HSP70 mRNA were determined by using the in situ hybridization. Results Compared with those in CIR group, the peaks of positive apoptosis in the CIH and CIRH groups were postponed, the amount of apoptosis was decreased obviously, and the ratio of Bcl-X_L/Bcl-Xs was higher, the expression of HSP70 mRNA in CIH group was significantly higher than that in CIRH group at different time points. Conclusion Mild Hypothermia has cerebral protective effects, and the therapeutic effects might be better in CIH group than in CIRH group.