Remote Ischemic Postconditioning Protect Rats Against Focal Cerebral Ischemia

Objective: Exploring the long-term neuroprotective effect of remote ischemic postconditioning after focal cerebral ischemia in rats. Methods : Sixty SPF male healthy Sprague Dawlay(SD) rats were randomly divided into four groups: Sham Group,MCAO Group,Rapid-RIPC Group and Delayed-RIPC Group and each group has 15 rats for texting the neurological deficit at five different time points after reperfusion. Except Sham group, the others use the modified Longa suppository preparation of focal cerebral artery ischemia model.Sham group(Sham operation group, n=15) : Fifteen male healthy Sprague Dawlay(SD) rats were administered Middle cerebral artery occllusion model,but did not deal with focal cerebral ischemia. MCAO group(Middle cerebral artery occllusion group, n=15):Fifteen male healthy Sprague Dawlay(SD) rats were administered 90 min Middle cerebral artery ischemia model. Rapid-RIPC group(Rapid Remote ischemic postconditioning group, R-RIPC n=15): After90 min MCAO model, Remote ischemic postconditioning was administered immediately after reperfusion by with drawing monofilament suture. The bilateral com femoral artery(BCFA) bluntly separated, at the beginning ofreperfusion or 6 hours after reperfusion, close/open them 5min in turn for 4circles by frog heart clip, namely remote ischemic postconditioning.Delayed-RIPC group : Delayed remote ischemic postconditioning was administered 6 hours after reperfusion by with drawing monofilament suture. All of the rats in each group were conducted neurological Function including motor and sensory function testing at 1d, 7d, 14 d, 21 d, 28 d after ischemia reperfusion.We complete the pathological examination at 30 d after ischemia reperfusion.Results: 1. cerebral infarction detection: The cerebral infarction size measured by HE staining show that compared with the Sham group, MCAO group, R-RIP and D-RIP group were significantly greater(P<0.05). Compared with the MCAO group, R-RIP slightly reduce the size of the infarct by 4.32%(P<0.05); 2.Motor function testing: Compared with the Sham group, the motor function scale of MCAO group was significantly greater(P<0.05). At the meantime,Compared with the MCAO group, D-RIPC has a more permanent motor function protective effect at 1d to 28 d after reperfusion(P<0.05). 3.Neuroprotection of sensory: Clearance rate of viscose experiment show that the right priority clearance rate was 76%. Then Stimulus intensity quantitative detection in each group show that Compared with the Sham group, Stimulus intensity of MCAO group was significantly greater(P<0.05). Compared with the MCAO group, D-RIPC has the long-time protection(P<0.05), But R-RIPC has discontinuous protective effect on sentory function detection. Conclusions:Remote ischemic postconditioning has the long-term neuroprotective effects in brain ischemia, especially D-RIPC.