ERK1/2参与丙泊酚预处理对肾性高血压大鼠离体心肌缺血再灌注损伤的作用

目的探讨丙泊酚预处理对肾性高血压大鼠离体缺血再灌注心肌的作用及细胞外信号调节激酶(ERK1/2)活化在其中的可能机制。方法在Langendorff离体心脏灌注模型上,64只肾性高血压大鼠随机分为8组(n=8):对照组(CTRL组),缺血再灌注组(ISCH组),DMSO组,30、100和300μmol.L-1丙泊酚预处理组(P30、P100和P300组),ERK1/2激酶抑制剂PD98059组(PD组)及PD98059+100μmol.L-1丙泊酚预处理组(PD+P100组)。持续监测心功能指标,实验末生化比色法检测心肌细胞超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,W estern B lotting方法半定量测定p-ERK1/2蛋白表达水平。结果再灌注60 m in末,ISCH组心功能较CTRL组恶化(P<0.01),DMSO组、P30组、P300组和PD组心功能指标与ISCH组相比未见差异,P100组心功能恢复程度高于ISCH组(P<0.01),PD98059能拮抗100μmol.L-1丙泊酚预处理引起的心功能改善。P100组MDA含量低于ISCH组和PD+P100组,SOD活性高于ISCH组和PD+P100组。P100组胞浆p-ERK1、胞核p-ERK1/2活性较ISCH组升高,PD+P100组较P100组胞核p-ERK1/2活性明显降低(P<0.01)。结论100μmol.L-1丙泊酚预处理减轻了肾性高血压大鼠离体心肌缺血再灌注损伤,其机制可能涉及心肌细胞p-ERK1/2,尤其是细胞核p-ERK1/2活性的增加。

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(P<0.01).Those in P100 group significantly improved compared to those in ISCH group(P<0.01),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.