Effects of hydrogen sulfide on myocardial apoptosis induced by acute myocardial ischemia

Objective To investigate the cardioprotective effects and the possible mechanism of hydrogen sulfide (H2S) in acute myocardial ischemia in rats.Methods Fourty-eight male SD rats were randomly divided into sham operation group,ischemia group,ischemia + NaHS low-,middle-and highdose groups and ischemia + DL-propargylglycine (PPG) group.Acute myocardial ischemia models were established by ligating the left anterior descending coronary artery.Saline was administrated in ischemia group.In ischemia + NaHS low-,middle-and high-dose groups and ischemia + PPG group,sodium hydrosulfide (NaHS) or PPG was respectively injected intraperitoneally at 3rd h after ischemia,and the wire was only threaded,not ligated in the sham operation group.All rats were killed at 6th h after the operation.The apoptosis of cardiac myocytes was examined by using flow cytometry.The expression levels of B cell lymphoma/lewkmia-2 (bcl-2) and bcl-2 associated X protein (bax) were detected by using immunohistochemisty.Results The apoptosis rate of myocardial cells in the ischemia group was (21.02 ± 0.70) ％,significantly higher than in the sham group [(9.07 ± 1.34) ％,P ＜0.01].The apoptosis rate of myocardial cells in the ischemia + NaHS low-,middle-and high-dose groups was (18.31 ± 1.79)％,(15.14 ±1.15) ％,and (12.03 ± 1.14) ％ respectively,significantly lower than in the ischemia group (P ＜ 0.05 or P ＜0.01),and that was (24.44 ± 1.90)％ in the ischemia + PPG group,significantly higher than in the ischemia group (P ＜ 0.01).The absorbance (A) value for the expression of bax in the ischemia group was (0.135 ±0.009),significantly higher than in the sham group (0.085 ±0.006),and that for bcl-2 in the ischemia group was (0.053 ± 0.008),significantly lower than in the sham group (0.074 ± 0.006) (P ＜0.01).The A value of bcl-2 expression in the ischemia + NaHS middle-and high-dose groups was (0.074 ±0.011) and (0.084 ±0.011) respectivdy,significantly higher than in the ischemia group.The A value of the bax expression in the ischemia + NaHS middle-and high-dose groups was (0.126 ±0.006) and (0.122 ±0.013),siguificantly lower than in the ischemia group (P ＜0.05 or P ＜0.01).As compared with the ischemia group,the A values of the bcl-2 expression in the ischemia + PPG group [(0.040 ±0.005)]was significantly reduced,and those of the bax expression [(0.154 ± 0.008)] were significantly increased (P ＜ 0.05).Conclsion Exogenous administration of H2S can significantly alleviate the myocardial injury probably by inhibitong the apoptosis of cardiomyocytes in acute myocardial ischemia. Key words: Hydrogen sulfide ;  Acute myocardial ischemia ;  Apoptosis ;  B cell lymphoma/lewkmia-2;  B cell lymphoma/lewkmia-2 associated X protein