Observation On Stereology Of Cell Apoptosis In Cerebral Cortex After Cerebral Ischemia Reperfusion In The Rats

In order to analyze the cell apoptosis changes in cerebral cortex at various time points after cerebral ischemia-reperfusion in the rats,42 Sprague-Dawley rats were randomly divided into seven groups which were control group,15min reperfusion of 6h,12h,24h groups and 2h-ischemia reperfusion of 6h,12h,24h groups,each group included six rats.The animal model of cerebral ischemia-reperfusion was made by ligating of the left common carotid artery and clamping of the right common carotid artery for 15min or 2h.The changes of cell apoptosis were observed by Hoechst33258 fluorescein stain and Bax immunohistochemical method,and the volume density(Vv)and the numerical density(Nv)of Bax positive cells and apoptotic in different regions of cerebral cortex was evaluated by stereology.The results showed as followed:1)Hoechst33258 fluorescein stain:the nucleus of apoptotic cell showed bright blue fluorescence under ultraviolet.The Vv and Nv of apoptotic cells in different regions of cerebral cortex in experimental group were significantly increasing compared with control group(P＜0.01).In the three 15min-ischemia reperfusion groups,the changes with the Vv and Nv of apoptotic cells in different regions of cerebral cortex between at various time points after cerebral ischemia reperfusion:at 12h after reperfusion the Vv and Nv of apoptotic cells in cerebral cortex significantly increased(P＜0.05),at 24h after reperfusion it significantly increased(P＜0.01)in hippocampl CA1,CA2 and parietal cortex.In the three 2h-ischemia reperfusion groups,the changes with the Vv and Nv of apoptotic cells in different regions of cerebral cortex between at various time points after cerebral ischemia reperfusion:at 12h after reperfusion the Vv and Nv of apoptotic cells in cerebral cortex significantly increased(P＜0.01),at 24h after reperfusion it significantly increased(P＜0.01)in hippocampl CA1,CA2 and parietal cortex.The Vv and Nv of apoptotic cells in cerebral cortex in three 2h-ischemia groups increased distinctly(P＜0.05 or P＜0.01)compared with that in 15min-ischemia groups. The differences between the Vv and Nv of apoptotic cells in different regions of cerebral cortex:in the hippocampus,the Vv and Nv of apoptotic cells in CA1 were biggest,and that in CA2 were bigger than that in CA3 and CA4(P＜0.05),and it was significantly differences between CA1 region and the other regions in hippocampus (P＜0.01),but no distinct differences between CA3 and CA4(P＞0.05).Compared with the hippocampus and dentate gyms,the Vv and Nv were bigger in parietal cortex(P＜0.01).The Vv in hippocampus was bigger than that in dentate gyrus(P＜0.01),but there was no distinct differences in Nv(P＞0.05).2)The result of Bax immunohistochemieal method:the cytoplasm and nucleus of the Bax positive cell both were stained brown,and most of the Bax positive cells were pyramidal cells.The Vv and Nv of Bax positive cells in different regions of cerebral cortex in experimental group were significantly increasing compared with control group(P＜0.01).In the three 15min-ischemia reperfusion groups,the changes with the Vv and Nv of Bax positive cells in different regions of cerebral cortex between at various time points after cerebral ischemia-reperfusion:at 12h after reperfusion the Vv and Nv of Bax positive cells in cerebral cortex significantly increased(P＜0.05),at 24h after reperfusion it significantly increased(P＜0.01)in hippocampl CA1,CA2 region and parietal cortex.In the three 2h-ischemia reperfusion groups,the changes with the Vv and Nv of Bax positive cells in different regions of cerebral cortex between at various time points after cerebral ischemia-reperfusion:at 12h after reperfusion the Vv and Nv of Bax positive cells in cerebral cortex significantly increased(P＜0.01),at 24h after reperfusion it significantly increased(P＜0.01)in hippocampl CA1,CA2 region and parietal cortex.The Vv and Nv of a Bax positive cells in cerebral cortex in three 2h-ischemia groups increased distinctly(P＜0.05 or P＜0.01)compared with that in 15min-ischemia groups.The differences between the Vv and Nv of Bax positive cells in different regions of cerebral cortex:in the hippocampus,the Vv and Nv of apoptotic cells in CA1 were biggest,and that in CA2 were bigger than that in CA3 and CA4(P＜0.05),and it was significantly differences between CA1 region and the others region in hippocampus (P＜0.05 or P＜0.01),but no distinct differences between CA3 and CA4(P＞0.05). Compared with the hippocampus,the Vv and Nv were bigger in parietal cortex(P＜0.01).Bax didn't express in dentate gyrus.Apoptotic mechanism was involved in the cerebral ischemia-reperfusion injury. And the time of cerebral ischemia-reperfusion impacted the cell apoptosis.The extent of cell apoptosis in different regions of cerebral cortex was different after cerebral ischemia-reperfusion.