NCX1&NCX3Involved In Cerebral Protection Induced By Remote Postconditioning Of Trauma In MCAO Rats

Objective:To observe the protective effects of remote postconditioning of trauma against ischemic-reperfusion injury, and to investigate whether NCX1&NCX3are involved in this cerebral protection in MACO rats.Methods:Forty-five adult male Sprague-Dawley rats were divided randomly into three groups (n=15, each group):Sham group, I/R group and Tra-Post-6h group. The rats in I/R and Tra-Post-6h group were received right middle cerebral artery occlusion (MCAO), and the rats in Tra-Post-6h group were accepted2cm abdominal incision at the6th hour of reperfusion in middle cerebral artery. The rats in Sham group were isolated the vessels, but didn’t receive right middle cerebral artery occlusion. All the rats were evaluated by the modified neurological severity score (mNSS) at6h&24h after cerebral reperfusion. Five rats were randomly selected to measure their cerebral infarct size by TTC staining; and another five rats were randomly selected to observe the tissue morphology by HE staining, detect the survival nerve cells by Nissl staining. The expression of NCX1&NCX3in the penumbra cortex were surveyed by immunohistochemical analysis and western blot analysis.Results:1.TTC staining:Compared with that in I/R group, the brain infarction volume in Tra-Post-6h group decreased significantly (P<0.05). There was no brain infarction in sham group.2.HE staining:The neurons of the penumbra cortex were eumorphism in Sham group. Compared with that in I/R group, the neurons in penumbra cortex in the Tra-Post-6h group were more clear and integrated. Contrarily, the quantity of neurons was also more but the interstitial edema were alleviative in penumbracortex in Tra-Post-6h group.3.Nissl staining:the number of survival neurons of penumbra cortex in Tra-Post-6h group increased significantly compared with that in I/R group (P＜0.05); and both Tra-Post-6h group and I/R group the quantity of survival neurons in the penumbra cortex were less than the Sham group (P<0.05).4. Immunohistochemical analysis and western blotting:Compared with that in Sham group, the expression of NCX1&NCX3in the penumbra cortex in Tra-Post-6h group decreased significantly (P<0.05). The expression of NCX1&NCX3in Sham group and I/R group were no difference(P>0.05).6. The mNSS in3groups no matter between groups or within group were no significant difference (P>0.05).Conclusion:remote postconditioning of trauma may have protective effects against cerebral I/R injury, which may related to decrease the expression of NCX1&NCX3in the penumbra cortex.