Phspho-ERK1/2 involved in propofol preconditioning on ischemia/ reperfusion injury in isolated renal hypertension rat hearts

Aim To explore the effect of propofol preconditioning on myocardial ischemia/reperfusion injury and the role of phspho-ERK1/2 during the propofol preconditioning in renal hypertension rat(RHR).Methods The isolated RHR hearts perfused on langendorff apparatus were randomly divided into 8 groups(n=8 each).After 20 min of perfusion for equilibration,the CTRL group was subsequently perfused by 148 min.The ISCH group was submitted to 35 min of ischemia and 60 min of reperfusion(I/R) to induce ischemia/reperfusion injury.The DMSO group was given by once 18 min and twice 10 min K-H solution containing 20 μmol·L~(-1) DMSO and 5 min K-H solution reperfusion prior to I/R procedure.The three propofol preconditioning groups were preconditioned by giving 2 cycles of 10 min K-H solution containing 30 μmol·L~(-1),100 μmol·L~(-1) or 300 μmol·L~(-1) propofol and 5 min K-H solution reperfusion prior to the I/R procedure.The PD group and the PD+P100 group were given K-H solution containing 20 μmol·L~(-1) PD98059,an ERK1/2 kinase specific inhibitor,for 18 min and 5 min K-H solution washout before I/R and 100 μmol·L~(-1) PPC respectively.Cardiac functional indices were recorded.Activity of SOD and content of MDA were measured.The level of phspho-ERK1/2 protein expression was measured using Western Blotting.Results Compared with those in the CTRL group,the recovery of cardiac functional indices in ISCH group became worse(P0.01).Those in P100 group significantly improved compared to those in ISCH group(P0.01),and pretreatment of 20 μmol·L~(-1) PD98059 abolished its protective effect.The myocardial content of MDA in P100 group was less than those in CTRL group and in PD+P100 group,but the myocardial activity of SOD in P100 group was higher than those in CTRL group and in PD+P100 group.The level of cytosolic and nuclear phspho-ERK1/2 protein expression in P100 group was higher than those in ISCH group and in PD+P100 group.Conclusion 100 μmol·L~(-1) propofol preconditioning reduced cardiac ischemia/reperfusion injury in isolated renal hypertension rat.The increase of myocardial phspho-ERK1/2,especially the nuclear one,may be involved in this effect.