ABSTRACT
AIM:To investigate the effect of ischemic postconditioning ( IPC) on autophagy induced by focal cerebral ischemia reperfusion ( I/R) in rats.METHODS:Healthy male SD rats were assigned randomly into sham-opera-tion (sham) group, I/R group and IPC group with 10 rats in each group.The rats in sham group were only exposed the right common , internal and external carotid artery surgically .The rats in I/R group were subjected to right middle cerebral artery occlusion (MCAO) by the modified Longa suture method for 2 h followed by 24 h of reperfusion.The rats in IPC group were subjected to MCAO for 2 h followed by reperfusion of the ipsilateral common carotid artery occlusion for 10 s for 5 episodes, and then reperfusion for 24 h.Autophagy was obeserved by transmission electron microscopy (TEM).The pro-tein levels of mammalian target of rapamycin (mTOR), p-mTOR and microtubule associated protein light chain 3 (LC3)-II in brain tissue of the rats were determined by Western blot .Pathological changes of brain tissue were observed by HE staining.RESULTS:The protein levels of mTOR and p-mTOR in IPC group were significantly higher than those in I/R group (P<0.05).The expression of LC3-II in IPC group was significantly lower than that in I/R group (P<0.01).The cerebral infarction area and brain water content in IPC group were significantly lower than those in I /R group (P<0.01). HE staining showed that neurons degeneration and necrosis in IPC group were significantly alleviated compared with I /R group.TEM observation showed that IPC revealed fewer autophagosomes , with much less severe cell damage than that in I/R group.CONCLUSION:IPC reduces brain ischemia reperfusion damage by decreasing autophagy of brain cells , which might be related to the activation of mTOR .
ABSTRACT
AIM:To investigate the effect of ischemic postconditioning ( IPC) on autophagy induced by focal cerebral ischemia reperfusion ( I/R) in rats.METHODS:Healthy male SD rats were assigned randomly into sham-opera-tion (sham) group, I/R group and IPC group with 10 rats in each group.The rats in sham group were only exposed the right common , internal and external carotid artery surgically .The rats in I/R group were subjected to right middle cerebral artery occlusion (MCAO) by the modified Longa suture method for 2 h followed by 24 h of reperfusion.The rats in IPC group were subjected to MCAO for 2 h followed by reperfusion of the ipsilateral common carotid artery occlusion for 10 s for 5 episodes, and then reperfusion for 24 h.Autophagy was obeserved by transmission electron microscopy (TEM).The pro-tein levels of mammalian target of rapamycin (mTOR), p-mTOR and microtubule associated protein light chain 3 (LC3)-II in brain tissue of the rats were determined by Western blot .Pathological changes of brain tissue were observed by HE staining.RESULTS:The protein levels of mTOR and p-mTOR in IPC group were significantly higher than those in I/R group (P<0.05).The expression of LC3-II in IPC group was significantly lower than that in I/R group (P<0.01).The cerebral infarction area and brain water content in IPC group were significantly lower than those in I /R group (P<0.01). HE staining showed that neurons degeneration and necrosis in IPC group were significantly alleviated compared with I /R group.TEM observation showed that IPC revealed fewer autophagosomes , with much less severe cell damage than that in I/R group.CONCLUSION:IPC reduces brain ischemia reperfusion damage by decreasing autophagy of brain cells , which might be related to the activation of mTOR .