Effects Of Combined Limb Remote Ischemic Postconditioning And Electroacupuncture On Brain Focal Ischemia And Reperfusion Injury In Rats

OBJECTIVE To explore the protective effect of combined limbremote ischemic postconditioning and electroacupuncture on brain focalischemia and reperfusion injury in rats，and to investigate the neuroprote-ctive effects of RIP against focal cerebral I/R injury.METHODS Part Ⅰ Ninety male SD rats weighing220~250g wererandomly assigned to5groups(n=18): sham-operated group （S）,ischemia/reperfusion group(I/R), Remote ischemic postconditioninggroup(RIP), Electroacupuncture group(EA), EA+RIP group（COM）.Thebrain ischemia reperfusion(I/R) model was induced by middle cerebralartery occlusion(MCAO). After the neurologic deficit scores wereevaluated, the brains were taken out to measure the infarct volume and toobserve the survival neurons in hippocampal CA1region. The expressionof Bax and Bcl-2was detected by Immunohistochemistry，and some brainswere obtained to mesure superoxide dismutase(SOD) activity andmalondialdehyde(MDA) content. Part Ⅱ Ninety male SD rats aged weighing220~250g were randomlyassigned to5groups(n=18)： sham-operated (S) group，ischemia/reperfusion(I/R) group,Remote ischemic postconditioning(RIP)group， The LY294002（Akt Inhibitors）+I/R+RIP group(LY)，TheNCX3siRNA+I/R+RIP group(SI). After the neurologic deficit scoreswere evaluated, the brains were taken out to measure the infarct volumewith TTC staining and to observe the survival neurons in hippocampal CA1region with the same methed as Part Ⅰ。 Some brains were obtained tomesure superoxide dismutase(SOD) activity and malondialdehyde(MDA)content; The Akt protein,p-AKT protein,NCX3protein expression ofhippocampal were evaluated by western blotting.RESULTSPart Ⅰ①Compared with I/R group,EA group and RIP group both showed lowerneurological deficit score(P<0.05), less infarct volume (P<0.05), moresurvival neurons; The expression of Bcl-2protein increased after RIP orEA compared with I/R at the same time point, while the expression ofBax protein decreased; And the effect of combined limb remoteischemic postconditioning and electroacupuncture was more obvious.②Compared with sham group,the content of cerebral tissue MDA wasmarkedly increased,and the activity of SOD was decreasedsignificantly in I/R group. Compared with I/R group, in EA group and RIP group, the activity of SOD in the cerebral tissues were enhanced,and the content of MDA were decreased（P<0.05.Furthermore, EA+RIPgroup showed more obvious effects.Part Ⅱ①Compared with I/R group，RIP group showed lower neurological deficitscore(P<0.05), less infarct volume (P<0.05) and more survivalneurons(P<0.05); while SI group and LY group both showed largerinfarct volume(P<0.05) and less survival neuronal (P<0.05) whencompared to the RIP group.②Compared with I/R group，the content of cerebral tissue MDA wasmarkedly decreased,and the activity of SOD was significantlyincreased in RIP group(P<0.05), Compared with RIP group, theactivity of SOD in the cerebral tissues were decreased,and the contentof MDA were increased（P<0.05）in SI group and LY group③The expression of Akt protein showed no diffrience in each group.Compared with I/R group, the expression of p-Akt protein weresignificantly increased in RIP group and SI group（P<0.05）, while inLY group,the expression of p-Akt protein was markedly decreasedcompared with RIP group（P<0.05）; Compared with I/R group, theexpression of NCX3protein was significantly increased in RIP group（P<0.05）, compared with RIP group, the expression of NCX3protein was markedly decreased in SI group（P<0.05）. Conclusion①RIP and EA are able to reduce infarct volume, increase survival ofneurons, while reducing lipid peroxidation products MDA content,SOD activity increased so as to reduce ischemia/reperfusion braininjury..②Joint use of EAand RIP can enhance the effects of brain protection.③The potential mechanism of neuroprotection induced by RIP isassociated with PI3K/Akt pathway,and RIP induced the up-regulatingof NCX3that was mediated by the PI3K/Akt pathway.