【摘要】 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7.6%、12.4%、23.8%和29.4%)，显著高于缺血中心区(分别为6.9%、7.8%、7.9%和8.2%)，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。

Apoptosis and necrosis in the penumbral areaafter reversible focal cerebral ischemia in rats

ZHANG Junjian, RUAN Xuzhong, ZHANG Suming, etal. Department of Neurology, Tongji Hospital, Tongji Medical University, Wuhan 430030

【Abstract】 Objective To measure thenumber and anatomic distribution of apoptotic cells and necrotic cells as a function oftime after transient focal ischemia and to evaluate apoptotic and necrotic cell deathcorrelated to the dynamics of penumbra evolution. Methods The middlecerebral artery (MCA) of Wistar rats was occluded for 30, 60, 90, 120, and 180 minutes byan intraluminal filament and recirculation was carried out for 48 hours. The ischemic coreand penumbral area were studied and DNA fragmentation was detected in paraffin sectionswith the use of a terminal deoxynucleotidyl-transferase mediated dUTP-biotin nick endlabeling (TUNEL). Adjacent sections were examined histologically. Results Quantitativeanalysis of these sections showed that apoptotic cells were mainly distributed in thepenumbra whereas necrotic cells were located mostly in the ischemic core. The percentageof apoptotic cells in the penumbra increased significantly at all time points after 60minutes of MCA occlusion (P<0.01), but the percentage of necrotic cells did not increasesignificantly (P>0.05) after 90 minutes of MCA occlusion. Conclusions Apoptoticcell death was the major form of the progressive loss of cells in the penumbra. Apoptoticcell death may contribute to the expansion of the ischemic lesion.

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