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目的探讨脑缺血半暗带转归过程中神经细胞的死亡机制。方法采用大鼠大脑中动脉（ＭＣＡ）闭塞及再通模型，ＭＣＡ闭塞时间分别为３０、６０、９０、１２０和１８０分钟，再灌流４８小时，用ＨＥ染色和ＴＵＮＥＬ原位标记法分别对缺血半暗带和缺血中心区细胞坏死和凋亡的动态变化进行定量观察，并计算两种死亡细胞在缺血中心区和半暗带所占的百分比。结果脑缺血６０～１８０分钟的各时间点，半暗带的神经细胞凋亡率（分别为７６％、１２４％、２３８％和２９４％），显著高于缺血中心区（分别为６９％、７８％、７９％和８２％），并随缺血时间的延长而显著升高，细胞坏死率在缺血９０分钟以上时无明显变化。结论脑缺血半暗带恶化过程中神经细胞死亡以及由此所引起的不可逆性损伤病灶的扩大，可能主要是通过细胞凋亡机制实现的。
Objective To investigate the mechanism of neuronal death in the process of cerebral ischemic penumbra. Methods MCA occlusion and recanalization models were performed in rats. The MCA occlusion time was 30, 60, 90, 120 and 180 minutes, respectively. After reperfusion for 48 hours, the rats were sacrificed respectively by HE staining and TUNEL in situ labeling The changes of cell necrosis and apoptosis in the penumbra and ischemic center were observed quantitatively and the percentages of the two kinds of dead cells in the ischemic center and penumbra were calculated. Results The apoptotic rates of penumbra neurons (76%, 124%, 238% and 294% respectively) at 60 ~ 180 minutes after cerebral ischemia were significantly higher than those in the absent (69%, 78%, 79%, 82%, respectively) in the blood center area and significantly increased with the prolongation of ischemia time. The necrosis rate of cells was no more than 90 minutes after ischemia obvious change. Conclusion The death of nerve cells and the expansion of irreversible lesion in the process of cerebral ischemic penumbra may be mainly through the mechanism of apoptosis.