Role of nuclear factor-E2 related factor 2-antioxidant response element pathway in cardio-protection by ischemic or pinacidil postconditioning against ischemia-reperfusion injury in isolated rat hearts / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of nuclear factor-E2 related factor 2 (Nrf2)-antioxidant response element (ARE) pathway in cardio-protection by ischemic or pinacidil postconditioning ( IP,PP) against ischemia-reperfusion (I/R) injury in isolated rat hearts.Methods Fifty-six male SD rats of both sexes weighing 200-250 g were anesthetized with intraperitoneal amobarbital sodium.The isolated rat hearts were perfused in a Langendorff apparatus with Krebs-Hensleit buffer (K-H).Fifty-six isolated rat hearts with I/R injury were randomly divided into 7 groups ( n =8 each)normal control group (group C) ; group I/R; group IP and group PP1-4 postconditioning with 4 different concentrations of pinacidil.After 20 min of equilibration,the perfusion was suspended for 40 min (global ischemia) followed by 60 min of reperfusion in group I/R.In group IP after 40 min of global ischemia,the isolated hearts underwent 6 cycles of 10 s reperfusion and 10 s ischemia followed by 58 min of reperfusion.In group PP1-4 at the end of 40 min of global ischemia,the isolated hearts were perfused with K-H containing pinacidil 5,10,30 and 50μmol/L for 5 min respectively followed by 55 min reperfusion with regular K-H.Left ventricular developed pressure (LVDP) and LVEDP were measured immediately before global ischemia and at the end of 60 min reperfusion.Myocardial specimens were obtained at the end of reperfusion for detection of Nrf2,quinopeoxidoreductase (NQO1),HO-1 and SOD1 mRNA (by RT-PCR) and protein (by Western blot) expression.Results I/R significantly up-regulated Nrf2,NQO1,HO-1 and SODI mRNA and protein expression,decreased LVDP and increased LVEDP in group I/R as compared with group C.IP and 30,50 μmol/L pinacidil postconditioning further significantly increased Nrf2,NQO1,HO-1 and SOD1 mRNA and protein expression and IP,5,10,30,50 μmol/L pinacidil postconditioning significantly increased LVDP and decreased LVEDP as compared with group I/R.Conclusion Ischemic or pinacidil postconditioning can attenuate I/R injury by activating Nrf2-ARE pathway in isolated rat hearts.