Effects of H_2 O_2 Pretreatment on Rat Myocardial Hypoxia/Reoxygenation Injury

Objective:To investigate the effect of H 2 O 2 pretreatment on apoptosis caused by hypoxia/reoxygenation in rat cardiac H 9 C 2 cells.Methods:The H 9 C 2 cells were cultured in vitro for amplification.The logarithmic growth phase cells were used to do the experimental treatment.H 9 C 2 cells were treated with 0,5,10,20,50 and 100 μmol/L concentration of H 2 O 2 respectively,in order to determining the optimal concentration of H 2 O 2 pretreatment.The effect of low concentrations of H 2 O 2 pretreatment on hypoxia/reoxygenation cell injury was observed.Cells were divided into 4 groups,control group,hypoxia/reoxygenation group,H 2 O 2 pretreatment group and AG 490 +H 2 O 2 group.AnnexinV-FITC/PI double staining method and FCM were used to detect apoptosis.MTT assay was used to detect the H 9 C 2 cell proliferation.Western Blotting method was used to detect STAT3 phosphorylation level.Results:The level of STAT3 phosphorylation was higher in H 9 C 2 cell group treated by 20 μmol/L H 2 O 2 than that of other groups.The myocardial cell apoptosis rates were significantly lower in H 9 C 2 cell group treat ed by 20 μmol/L H 2 O 2 than those of 50 and 100 μmol/L treatment groups.The myocardial cell proliferation was higher in 20 μmol/L H 2 O 2 treatment group than that of 50 and 100 μmol/L treatment groups,but no significant difference was found com pared with 10 μmol/L treatment group.The protective effect of H 2 O 2 pretreatment on oxygen injury was abolished after treat ment with AG 490.Conclusion:Protective effect of 20 μmol/L H 2 O 2 pretreatment on myocardial hypoxia/reoxygenation injury was by the activated JAK2-STAT3 pathways to inhibit cell apoptosis.