Effect of high temperature preconditioning on hydrogen peroxide-induced expression of mitochondrial metallothionein in rat cardiomyocytes / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of high temperature preconditioning on hydrogen peroxide (H2 O2)-induced expression of mitochondrial metallothionein (MT) in rat cardiomyocytes.Methods The rat cardiomyocytes H9C2 cultured in vitro were randomly divided into 3 groups (n =6 each):control group (group C) ;H2O2 group (group H2O2); high temperature preconditioning group (group HTP).The cells were continuously cultured for 3 h in group C.The cells were cultured for 3 h in serum-free DMEM liquid culture medium containing H2O2 0.5 mmol/L in an incubator filled with 5％ CO2 at 37 ℃ in group H2O2.In group HTP,the cells were cultured in serum-containing DMEM liquid culture medium,then placed in a warm bath of 42 ℃ for 1 h,cultured for 12 h in an incubator filled with 5％ CO2 at 37 ℃,DMEM liquid culture medium was then removed,and the other procedures were similar to those previously described in group H2 O2.Myocardial cell apoptosis was observed by flow cytometry.The apoptotic rate was calculated.The ultrastructure of myocardial mitochondria was examined with electron microscope.The expression of mitochondrial MT in cardiomyocytes was determined using Western blot.Results Compared with group C,the apoptotic rate was significantly increased,and the expression of mitochondrial MT was up-regulated in groups H2O2 and HTP (P ＜ 0.01).The apoptotic rate was significantly lower,and the expression of mitochondrial MT was higher in group HTP than in group H2O2 (P ＜ 0.01).The mitochondrial injury was attenuated in group HTP as compared with group H2 O2.Conclusion The mechanism by which high temperature preconditioning reduces H2 O2-induced myocardial damage may be related to up-regulation of expression of mitochondrial MT in cardiomyocytes and endogenous myocardium-protective mechanism in rats.