C2C12 myoblasts were grown to confluence in DMEM supplemented with 10% FCS. They were induced to differentiate into myotubes, by switching to DMEM containing 2% horse serum. Primary cultures of human skeletal muscle cells were initiated from satellite cells of quadriceps samples obtained from organ donors (3 men, 27 ± 7 years, 23 ± 1.7 kg/m2). Differentiated myotubes were prepared according to the procedure previously described in details (37). Myotubes were then cultured for 96 hours, with or without H2O2 (100µM), with mannitol (25mM) or glucose (25mM), and with BSA (1%) or palmitic acid (200µM), in the presence or not of N-acetylcysteine (NAC, 10mM).