Effects of Ischemic Postprocessing on Activation of Caspase-3 and Caspase-9 and Release of Cytochrome C in Reperfusion Injury after Cerebral Ischemia

Objective To investigate the effect of ischemic postprocessing on activation of Caspase-3 and Caspase-9 and release of cytochrome C in reperfusion injury after cerebral ischemia in rats.Methods Sixty adult SD male rats were randomly divided into sham opration group(group A,n =20),ischemia and reperfusion group(group B,n = 20) and ischemic postprocessing group(group C,n =20).The model of focal ischemic reperfusion was induced by intraluminal middle cerebral artery occlusion(MCAO) with a nylon monofilament suture.After 24 h of ischemia and reperfusion,the brain tissues were obtained for detecting.Apoptosis of intracephalic nerve cells was detected by in situ end labeling,and contents of Caspase-3,Caspase-9 and cytochrome C were detected by enzyme activity assay,Western blot and immunohistochemisty method.Results The amount of apoptosis cell in group B and C increased when compared with that in group A,and the differences were statistically significant(P 0.05);the amount of apoptosis cell in group C was significantly reduced when compared with that in group B(P 0.05).The activity rate of Caspase-3 and Caspase-9 was higher in group B and C than that in group A,while the activity rate in group C was abated when compared to that in group B,and the differences were statistically significant(P 0.05).Contents of pro-Caspase-3 and pro-Caspase-9 in group B and C were significantly reduced when compared to those in group A(P 0.05),and the contents in group C were significantly increased when compared to those in group B(P 0.05).In the cytoplasm,Cyt C was no obviously released in group A,while it was released obviously in group B and C,and the differences were statistically significant(P 0.05);Cyt C was released more obviously in group C than that in group B(P 0.05).In mitochondria,Cyt C leakage was more obvious in group C than that in group A,and it was significantly decreased in group C when compared to that in group B,and the differences were statistically significant(P 0.05).Conclusion Ischemic postprocessing may reduce apoptosis of nerve cells in reperfusion injury after cerebral ischemia,and may restrain the release of cytochrome C and activation of Caspase-3 and Caspase-9 in cerebral I/R injury.