Effect Of Etomidate Postconditioning On Expression Of NAIP And Caspase-3in Rats Following Ischemia-reperfusion

Objective：To investigate the effects of Etomidate postconditioning on expression ofNAIP and caspase-3in rats following ischemia-rep erfusion in order to provide theoreticalbasis for the perioperative etomidate brain protectionMethods: The model of cerebral ischemia-reperfu sion was set up by occluding thebilateral common carotid artery60min and reperfusion.A total of60healthy and adultmale SD rats,6-8W,weight220-250g,were randomly divided into four group（severy groupn=15）: sham operated group（Sham group）；Ischemia-reperfu sion（I/R group）; Etomidatepostconditioning0.3mg/kg group（Etp1group）;Etomidate postconditioning0.9mg/kggroup （Etp2group）;The rats in each group were further subdivided into3subgroups.according to the various reperfusion time（12h，24h and72h，n=5pertimepoint）.At63min before reperfusion，I/R and Sham group with1ml physiological salinewere injected by femoral vein,Etp1、2group with different dose of Eto（0.3mg/kg、0.9mg/kg）+physiological saline to1ml were injected by femoral vein.After the variousreperfusion,the rats were executed and the rats brain tissue were removed and thanconventional paraffin embedding.①brain tissue histological features and morphologicalchanges were observed by HE staining.②.The expression of NAIP and active-caspase-3were dectected by Immunohistochemical staining （S-P method）;Results：①Groups of brain tissue morphology:The nerve cells of Sham group werenormal form, but the other three groups had certain brain infarct size．Compared with theSham group,the neurons in hippocampal CA1were remarkable condensed and deeplystained cytoplasm in I/R group.Compared with the I/R group, the neurons in hippocampalCA1were remarkable increased in Etp1and Etp2group,but there was no obviousdifference between the two groups of Etp1and Etp2（P>0.05）.②Brain tissue NAIPexpression of groups:All the point there were almost no NAIP expression in Sham group. Compared with the Sham group, the number of NAIP-positive cells in hippocampal CA1was remarkable increased in I/R group（P<0.05）,and reached the peak at12h of reperfusionand then decreased gradually to the normal level on72h of reperfusion. Compared with theI/R group, the number of NAIP-positive cells in hippocampal CA1was remarkableincreased in Etp1and Etp2group all the point（P<0.05）,and reached the peak at24h ofreperfusion and a large number of NAIP-positive cells existed on72h of reperfusion,butthere was no obvious difference between the two groups of Etop1and Etp2（P>0.05）.③Brain tissue active-caspase-3expression of groups and apoptoic cells:Each timereperfusion point,there was a few of active caspase-3expression in Sham group. Comparedwith the Sham group, the number of active-caspase-3-positive cells and the rates of nervecelles apoptosis in hippocampal CA1was remarkable increased in I/R group（P<0.05）,andreached the peak at24h of reperfusion and then begain to decrease on72h of reperfusion.Compared with the I/R group,the number of active-caspase-3-positive cells in hippocampalCA1and the rates of nerve celles apoptosis were remarkable decreased in Etp1and Etp2group（P<0.05）,the number of pyramidal cells increased significantly.But there was noobvious difference between the Etp1and Etp2（P>0.05）groupConclusion：Etomidate postconditioning can protect the brain in rats followingischemia-reperfusion,it may relates to up-regulating the expression of NAIP anddown-regulating the expression of caspase-3,which can inhibit the neural cell apoptosis.