Abstract: AIM: To investigate the anti-apoptotic effects of R (+) and S (-) enantiomers of carvedilol in cardiac myocytes.METHODS: H9C2-1 cardiac myocytes were induced to apoptosis by isopropylarterenol(ISO) for 12 h, R (+) carvedilol or S (-) carvedilol was added as the treatment with 2 μmol·L^-1 or 10μmol·L^-1 dose.Apoptotic cells were identified by Hoechst 33258, and for the determination of apoptosis ratio,Annexin Ⅴ-FITC/ PI double-staining assay was applied with the flow cytometer.The apoptotic effect of 10 μmol R (+) (carvedilol) or S (-) carvedilol alone on cell was also measured.RESULTS: 2 mmol·L^-1 ISO induced a apoptosis in a great quantity of H9C2-1 cells (p<0.01) , and R (+) (carvedilol) or S (-) carvedilol could decreased the apoptotic ratio markedly(p<0.01).The late stage and total apoptotic ratios of 2 μmol·L^-1 R(+) carvedilol +ISO were lower than those of 2 μmol S (-) carvedilol +ISO group(p<0.05) ,but there is no significant difference between 10 μmol·L^-1 group.The apoptotic ratio of 10 μmol·L^-1 S(-) carvedilol itself was a little higher than that of control but was much lower than that of ISO groups (p<0.05).CONCLUSION: Both R (+) (carvedilol) and S (-) carvedilol can effectively inhibit the apoptosis of H9C2-1 cardiac myoctytes induced by ISO, and there is stereoselective difference in it's anti-apoptotic activity on cardiac myocytes between these two enantiomers.R(+) carvedilol is more potential to antagonize the cell apoptosis.

Key words: carvedilol, enantiomers, anti-apoptosis, cardiac myocytes