大鼠局灶性脑缺血神经细胞凋亡与坏死的研究

用凝胶电泳及原位末端标记研究大鼠脑缺血再灌流后神经元的凋亡与坏死。采用可逆性大脑中动脉阻塞２ 小时，再灌流０．５～４８ 小时，造成脑缺血再灌流模型（３０ 只），用ＨＥ、原位末端标记（ＴＵＮＥＬ）和琼脂糖凝胶电泳观察神经元的改变。结果：缺血损伤区位于视前区、纹状体和皮质，再灌流０．５ 小时，视前区的缺血损伤区有较多的凋亡细胞，而皮质、纹状体仅有散在的凋亡细胞。再灌流３～６小时，凋亡细胞数量增多，并可见坏死细胞，１２小时达高峰，持续到２４ 小时，并可见凋亡细胞各种形态，凋亡细胞主要位于缺血损伤区内界，坏死细胞也增多。４８小时完全坏死区周围有成群的凋亡细胞。电泳显示涂片状背景上有明显的ＤＮＡ带。细胞凋亡参与缺血再灌流所致的神经元损伤，凋亡细胞与坏死细胞并存，细胞凋亡使梗塞区面积扩大。

Apoptosis and Necrosis of Neuron after Focal Ischemia in Brain of Rats

This article reports the apoptosis and necrosis of neurons following ischemia reperfusion in the brain of rats. The focal ischemia model was established by occluding the middle cerebral artery for 2h and reperfusing for 0.5 48h. The neuronal changes were investigated by HE staining, TUNEL and agarose gel electrophoresis. The foci of ischemia were in the preoptic area, striatum and cortex. At 0.5h of reperfusion, there were quite a few apoptotic neurons in the preoptic ischemic focus, but only a few scattered apoptotic cells were seen in the striatum and cortex. During 3 6h of reperfusion, the number of apoptotic cells increased and the necrotic cells appeared. The number of apoptotic cells reached a peak at 12 24h and the in morphology varied, and they were mainly located in the inner boundary of infarct. At 48h, the apoptotic cells decreased; and the necrotic cells increased. Agarose gel electrophoresis showed the dense smear and ladder pattern of DNA fragments, the apoptosis and necrosis of neurons coexisted, and apoptosis contributed to the enlargement of the ischemic infarct.