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_4CA_2CA_3DG; 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.