Cadmium chloride-induced oxidative stress in skeletal muscle cells in vitro

The effects of cadmium chloride (CdCl2) on oxidative stress in the skeletal muscle cell line C2C12 were investigated. Myoblast cells that differentiated into myotubes were treated with CdCl2 (1, 3, 5, 7.5, 10, and 12.5 μM) for 24, 48, and 72 h. Subsequent assay of cell homogenates for MTT (3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide) reduction, neutral red uptake and nucleic acid content showed that cadmium was toxic to C2C12 cells in a concentration-dependent manner. Glutathione-S-transferase activity (nmol μg of protein−1 min−1) was increased with 1 and 3 μM CdCl2 (36.9 ± 5.6 and 32.1 ± 6.0, respectively) compared to control cells (21.8 ± 1.5), but decreased at higher concentrations (7.5 μM = 15.9 ± 3.3, 10 μM = 15.9 ± 4.6, and 12.5 μM = 10.5 ± 2.8). An increase in malondialdehyde content (nmol μg of protein−1), especially at high CdCl2 concentrations (control = 7.3 ± 0.5; CdCl2: 7.5 μM = 11.2 ± 3.1, 10 μM = 14.6 ± 3.8, and 12.5 μM = 20.5 ± 6.5) indicated that there was enhanced lipid peroxidation. Light and scanning electron microscopy showed that there was a concentration-dependent loss of adherent cells and the formation of vesicles indicative of cell death. These results indicated that CdCl2 increased oxidative stress in C2C12 cells, and this stress probably compromised cell adhesion and the cellular antioxidant defense mechanisms.