督脉穴位电针对暂时性脑缺血所致神经细胞死亡的影响

Effect of Electroacupuncture on Neuronal Death Induced by Cerebral Ischemia-reperfusion and Its Mechanisms

目的 :观察电针对神经细胞死亡、DNA损伤及凋亡相关基因蛋白 (Bcl 2、Bax、P53 )表达的影响。方法 :采用短暂脑缺血再灌注 (MCAo)模型 ,应用HE、TUNEL、免疫组织化学等实验技术进行观察。结果 :大脑中动脉阻塞 2hr后 ,随着再灌时间的增加梗塞灶面积进行性发展 ,在不同再灌时间点 ,电针均能减小梗塞面积 ,而且电针可明显减少短暂脑缺血再灌注后细胞坏死和DNA损伤 ,并上调Bcl 2 /Bax比值 ,和减少P53的表达。结论 :电针具有神经保护作用 。

Objective: To observe the protective effect of electroacupuncture (EA) against rat's cerebral ischemia induced by middle cerebral artery occlusion (MCAo). Methods: 30 SD rats were randomized into ischemia (2 hr) and reperfusion (IR) control group, and IR+EA group. Each group was further divided into three subgroups respectively according to the different time course of reperfusion: IR 24 hr group, IR 48 hr group, IR 72 hr group, and EA+IR 24 hr group, EA+IR 48 hr group and EA+IR 72 hr group, with 5 rats in each group. EA was applied to 'Baihui' (GV 20) and 'Renzhong' (GV 26) for 1 hr beginning from 15 min on after ischemia. After 24 hours' reperfusion, EA was performed on the same two points for 45 min everyday. Neuronal death and apoptosis associated proteins (Bcl 2, Bax,P53) expressions of the cerebral tissue sections were observed using HE staining, TUNEL (TdT mediated dUTP Nick End Labeling) and immunohistochemistry. Results: After IR, the cerebral infarction area increased progressively along with the increase of duration of the reperfusion, while that of 3 EA groups was smaller. There were significant differences between IR 24 hr group and EA+IR 24 hr group, between IR 48 hr group and EA+IR 48 hr group, and between IR 72 hr group and EA+IR 72 hr group ( P <0.05～0.01).The surviving rates of neurons in the striate body of the brain of EA+IR 24 hr group and in the cerebral cortex of EA+IR 48 hr group and EA+IR 72 hr group were significantly higher than those of the corresponding IR control groups respectively ( P <0.05).The TUNEL positive cell ratio of the cerebral cortex in each one of 3 EA groups was significantly lower than that of each corresponding IR control group ( P <0.05～0.001). The ratio values of Bcl 2 positive cells/Bax positive cells of 3 EA groups were all significantly higher than those of the 3 corresponding IR control groups ( P <0.05～0.001). P53 immuno reaction positive neurons of EA+IR 24 hr group and EA+IR 48 hr group were markedly fewer than those of IR 24 hr group and IR 48 hr group respectively ( P <0.05). It showed that EA could evidently reduce the neuronal death and apoptosis, up regulated Bcl 2/Bax and down regulated the expression of P53 in cerebral IR rats. Conclusion: The protective effect of EA on cerebral ischemic neurons may be related with the resultant regulation of the expression of apoptosis associated proteins (Bcl 2, Bax, P53).