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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 investigate the effects of mild hypothermia on neuronal apoptosis and expression of Bcl-XL, Bcl-Xs and HSP70 after focal cerebral ischemia in rats. Methods 140 adult healthy Wistar rats were randomly divided into sham-operation group, ischemia-reperfusion group (H0 group), hypothermia group immediately after ischemia (H1 group) and hypothermia group (H2 group) , The model of middle cerebral artery occlusion (MCAO) reperfusion was established by thread occlusion. The use of ice packs line hypothermia treatment, so that rat body temperature decreased. The expression of Bcl-XL, Bcl-Xs and HSP70mRNA in brain tissue were detected by in situ hybridization. Results The apoptosis-positive cells in hypothermia treatment group (H1 and H2) had the peak time delay, and the number was significantly decreased. The ratio of Bcl-XL to Bcl-Xs was significantly higher than that in H0 group. The expression of HSP70 in H1 group was significantly higher than that in H0 group In H2 group. Conclusion Mild hypothermia has neuroprotective effect. The effect of mild hypothermia immediately after cerebral ischemia is better than that of mild hypothermia after cerebral ischemia-reperfusion.