大鼠短暂性全脑缺血再灌注后海马神经元动态变化

采用股动脉放血并双侧颈总动脉夹闭制作大鼠全脑缺血再灌注模型,分别于术后6h、1d、3d、5d处死动物,取脑,制作石蜡切片和冰冻切片,通过HE染色、TUNEL检测及Caspase-3活性测定,对大鼠海马各区锥体细胞形态进行动态观察。结果表明:在短暂性全脑缺血中,海马锥体细胞存在着凋亡和坏死两种死亡形式,细胞凋亡在海马各区中的分布是一动态过程,各区对缺血易损伤性的顺序是:CA1及门区>CA2>CA3>齿状回;脑缺血再灌注不同时间,海马锥体细胞中DNA断裂及Caspase-3的表达与细胞凋亡呈现相似的变化趋势,且DNA的断裂早于Caspase-3的表达;与青年组相比,老年组海马神经元出现凋亡时间早且损伤严重。试验证明:在脑缺血再灌注损伤中,海马各区存在着缺血耐受性差异;细胞凋亡是神经元死亡的一种重要形式。

Changes of Pyramidal Cells in Hippocampus after Rat Transient Global Ischemia

In order to observe the changes of pyramidal cells in the hippocampus during cerebral ischemia-reperfusion bilateral carotid arteries occlusion model of rats were constucted and killed on 6 h,1 d,3 d and 5 d after reperfusion following 10 min forebrain ischemia,then paraffin and frozen sections were made and stained with HE,TUNEL and Caspase-3 methods. Results indicated there are two patterns of cell death: apoptosis and necrosis, in the course of rat transient global ischemia. The changes of apoptosis in pyramidal cells of hippocampus were different, and following the sequence of the selective vulnerability was:CA_1 and CA_4>CA_2>CA_3>DG; there are similar morphological changes on the DNA fragmetation in pyramidal cells of hippocampus and Caspase-3 expression in different reperfusion duration, but the time of DNA fragmetatin appeared was earlier than that of Caspase-3 expression; compared with that in young groups, the ischemic brain injury of old groups was severer and the advent of apotosis was earlier. It has been tested that the difference of ischemic tolerance exists in the regions of the hippocampus and apoptosis may be an important form in the course of cerebral ischemia-reperfusion(IR) injury.