局灶性脑缺血再灌注损伤神经细胞凋亡的研究

Experimantal Study on Focal Cerebral Ischemia and Reperfusion Injury

目的探讨局灶性脑缺血再灌注损伤后神经细胞凋亡和不同时间点脑组织病理学改变及相应时间点大鼠神经功能评分的关系.方法将成年Wistar大鼠55只,随机分为脑缺血组、假手术对照组、脑缺血再灌注组,应用线栓法制备局灶性脑缺血再灌注模型,并采用HE染色TUNEL法检测再灌注损伤后细胞凋亡情况.电镜观察脑缺血再灌注后细胞凋亡形态的改变.结果脑缺血再灌注0～6 h神经功能缺损程度最重,随再灌注时间延长逐渐改善,24 h症状又有加重,提示再灌注引起继发性脑损害.神经细胞出现坏死或凋亡与缺血程度和持续时间有关.TUNEL标记缺血1 h后再灌注48 h之内,皮层区细胞凋亡指数(AI)随再灌注时间的延长不断增加.结论线栓法成功制备的大鼠局灶性脑缺血再灌注模型,可用于缺血再灌注神经细胞损害及脑保护的研究.缺血性神经原死亡经历凋亡和坏死两种途径,中度、重度缺血以坏死为主,轻度缺血以凋亡为主.

Objective To observe brain histopathological changes at different time points after focal cerebral ischemia and reperfusion, and the relation between them and the nerve function score at the corresponding time. Methods To make use of the focal cerebral ischemia and reperfusion model induced by a suture method which preferred by Zea Longa in rats, 55 adult Wistar rats randomly allocated to the ischemia group, sham-operation group, ischemia and reperfusion group, five rats in each group. HE staining and TUNEL method were used to investigate the neuron apoptosis and test neuronal apoptosis histopathology by electron microscope after cerebral ischemia and reperfusion. Results Neuronal function deficit was most serious in 0- 6 h after reperfusion, after that the function became better, while being exacerbated after 24 h. TUNEL assay showed that within 48 h of refperfusion, cellular AI in the cortex increased with prolong of the reperfusion time. Conclusions Focal cerebral ischemia and reperfusion model induced by a suture method in rats is successfully used in this trial to study the mechanism of cellular damage and cerebral protection after ischemia and reperfusion. The neuronal death after ischemia is via apoptosis and necrosis. Moderate to severe ischemia mainly results in necrosis, while mild ischemia mainly results in apoptosis.