Anti-apoptotic effect of L-carnitine on H_2O_2-induced cardiomyocytes via inhibition of calcineurin overexpression

Aim To explore whether calcineurin(CaN) was involved in the inhibitory effect of L-carnitine on H2O2-induced cardiomyocyte apoptosis. Methods Neonatal rat cardiomyocytes were randomly divided into control,H2O2,L-carnitine + H2O2and CsA+ H2O2groups. Control group was treated with normal saline; H2O2group was challenged by 200 μmol·L- 1H2O2for 12 h; L-carnitine + H2O2and CsA + H2O2groups were pretreated with 1. 2 mmol ·L- 11 h or 1μmol·L- 1CsA 30 min prior to 12 h H2O2stimulation,respectively. Cell apoptotic rate was evaluated by flow cytometry,and expression of apoptosis relevant protein including cleaved caspase-3,Bcl-2,Bax and CaN was determined by Western blot. Results Compared with control,H2O2treatment induced a significant increase of cardiomyocyte apoptosis. Meanwhile,expression of pro-apoptotic proteins cleaved caspase-3and Bax increased,and anti-apoptotic protein Bcl-2decreased. L-carnitine and CsA(a specific inhibitor of CaN),significantly attenuated above-mentioned abnormalities. And also,L-carnitine greatly inhibited the overexpression of CaN induced by H2O2. Conclusion L-carnitine attenuates cardiomyocyte apoptosis via modulating CaN expression.