Effect Of Nrf2 On Ischemic Rat Myocardium Using Ischemia/drug Postconditioning

Objective:Constructing rat ischemia/reperfusion injury(IRI) model to investigate the protective effect of postconditioning on ischemic rat myocardium which suffered IRI, and to explore the effect of Nrf2/ARE pathway on ischemic myocardium using ischemia and emulsified isoflurane postconditioning. Methods: Langendorff apparatus were used to establish the model of myocardial ischemia reperfusion injury.40 male Sprague-Dawley rats randomly chosen were divided into 5 groups(n=8, each group), i.e. the normal group(N), the control group(C), the ischemic postconditioning group(IPO), the emulsified isoflurane postconditioning group(E), the fat emulsion postconditioning group(F), each group of rats being poured into with K-H for 20 minutes for equilibration. Group N:went on perfusion for another 100 minutes after equilibration; Group C:perfusing 4℃ST Thomas liquid to make the heart stop beating after equilibration, and then underwent 40 minutes global ischemia and followed by 60 minutes reperfusion; Group IPO:after 40 minutes global ischemia, then reperfusion for 10 seconds and then ischemia for 10 seconds.The above procedures were repeated 6 times and then reperfusion 58 minutes; Group E:after 40 minutes global ischemia, perfusing emulsified isoflurane(5mmol/L) 2 minutes before reperfusion, then reperfusion 58 minutes; Group F:after 40 minutes global ischemia, perfusing 30% fat emulsion 2 minutes before reperfusion, then reperfusion 58 minutes. Investigating the cardiac function of each group at the point of equilibration and reperfusion end. To detect the gene transcription and the protein expression of Nrf2, NQO1, GCLC of the samples from left ventricle obtained after reperfusion, we used the methods of PCR and Western blotting. Results:1. The cardiac function:There was no obvious difference between each group after equilibrium. After reperfusion, group N, IPO, E, F were obviously better than group C, while group IPO and E were obviously better than group F.2. PCR Nrf2 and GCLC:group C, IPO, E, F were obviously higher than group N, group E were obviously higer than other groups, group C, IPO and F were no obvious difference; NQO1:group C, IPO, E, F were obviously higher than group N, group C, IPO, E, F were no obvious difference.3. Western blotting Nrf2 and GCLC:group C, IPO, E, F were obviously higher than group N, group E were obviously higer than other groups, group C, IPO and F were no obvious difference; NQO1:group C, IPO, E, F were obviously higher than group N, group C, IPO, E, F were no obvious difference. Conclusions:1. Ischemia/emulsified isoflurane/fat emlsion postconditioning could alleviate rat myocardium ischemia/reperfusion injury, improve cardiac function. To contrast with fat emulsion postconditioning, ischemic and emulsified isoflurane postconditioning could attenuate rat myocardium ischemia-reperfusion injury more inffecient, had stronger rat myocardial protection effect.2. Nrf2 which could upregulate antioxidants contributed to the effect of myocardial protection produced by emulsified isoflurane postconditioning and the expression value of antioxidants induced by Nrf2 are different.3. Ischemia reperfusion injury could upregulate Nrf2, and then upregulate antioxidants through Nrf2/ARE pathway.