HYDROGEN SULFIDE EXERTS PROTECTIVE EFFECTS AGAINST OXIDATIVE STRESS IN CULTURED H9C2 MYOCYTES

The endogenous hydrogen sulfide (H2S) is produced enzymatically in various species. At low concentrations, this gasotransmitter limits apoptosis and activates mitochondrial K+ATP channels. This study was designed to investigate the mechanisms of action of H2S donors in protecting cultured myocytes against oxidative stress. An immortalized myoblasts line (H9c2) was used to this purpose: cells were kept in DMEM enriched with fetal bovine serum (10%) and penicillin/streptomycin (1%). The experimental groups have been divided as follows: Group 1) oxidative stress was induced by incubation with 400 mM H2O2, Group 2) H9c2 were treated with different concentrations (0.1, 1, 10, 100 mM and 1 mM) of H2S and after 24 h challenged with 400 mM H2O2. After 2 h in H2O2 medium samples were collected and the concentration of lactate dehydrogenase (LHD) was measured with spectrophotometric assays. In Group 3 cells were lysed after treatment with H2S in the absence of H2O2 challenge. A dose-dependent protective activity with a maximal reduction of LDH release at 10 mM H2S (50% reduction compared to Group 1) was observed. At higher doses the protective effect disappeared. Western blot showed a marked increase of phosphorylated p-44/p/42 MAPK in cells treated with 10 mM H2S. Data suggest that pre-treatment with low doses of H2S exerts protective effects on myoblasts against oxidative stress through a cascade that includes p44/p/42 MAPK activation.