Experimental Study Of Cell Apoptosis Mechanism With Focal Cerebral Ischemia And Reperfusion In Rabbit

Objective To analyze the dynamic changes of apoptosis in brain of rabits after acute ischemia-reperfusion,and relationship with nNOS and Survivin,further to investigate the apoptosis mechanism of brain cell in rabbits after ischemia and reperfusion.Methods 58 New Zealand white rabbits were randomly divided into permanent ischemia group(group A) and reperfusion group(group B),and made into middle cerebral artery ischemia model using introluminal thread technique.Group A(A₁-A₆) were separated into several group by time after ischemia,1 h,3h,6h,12h,24h,48h,each group has five ones. Group B(B₁-B₆) ischemialh and reperfusion in 0h(5),2h(5),5h(5),11h(4),23h(5),47h (4).Another 10 was false surgery group,as control group to group A and B.Each took diffusion imaging in different time point,and immediately decapitated brain.Respectively go on with HE staining,detection to apoptosis,Survivin and nNOS.Be attention to the morphological changes of ischemic tissue under microscope,and record the positive cells of apoptosis,Survivin and nNOS.Results Permanent ischemia group and ischemic-reperfusion group showed apoptotic cells increased first and downward later,but permanent group is more than reperfusion group at different time points.Survivin positive cells of reperfusion group at different time is more than permanent group,the peak is at 12h,there is a significant correlation between apoptosis and Survivin(r=0.963,P=0.002).nNOS cells of reperfusion group is more than permanent group too,the whole trend is rising after declining,and the low peak is at 12h.The change of nNOS is similar to apoptosis in trend but oppsite in direction(r=-0.942,P=0.005).Conclusion 1.Cerebral ischemia may induce Survivin expression increases,this change may be able to protect the brain tissue at certain extent.And in the period of reperfusion,formation of nNOS may be the protective effects of nerve cells on the verge of apoptosis.2.6h of ischemia is the time window of thrombolytic therapy,reperfusion in this time window may save some brain tissues in penumbral zone.