Effects of l-carnitine against H2O2-induced oxidative stress in grass carp ovary cells (Ctenopharyngodon idellus)

This study was designed in vitro to investigate the effects of l-carnitine against H2O2-induced oxidative stress in a grass carp (Ctenopharyngodon idellus) ovary cell line (GCO). GCO cells were pre-treated with different concentrations of l-carnitine, followed by incubation with 2.5 mM H2O2 for 1 h to induce oxidative damage. The results indicated that adding l-carnitine at concentrations of 0.01–1 mM into the medium for 12 h significantly increased cell viability. Pre-treatment with l-carnitine at concentrations of 0.1–5 mM for 12 h significantly inhibited 2.5 mM H2O2-induced cell viability loss. The significant decreases in the level of reactive oxygen species and cell apoptosis were observed in 0.5 mM l-carnitine group compared to the H2O2 group. Malondialdehyde values of all of the l-carnitine groups were significantly lower than those of the H2O2 group, while total glutathione levels of all of the l-carnitine groups were significantly higher than of the H2O2 group. The activity of antioxidant enzymes, such as total superoxide dismutase (0.1 and 0.5 mM l-carnitine), catalase (0.5 mM l-carnitine) and γ-glutamyl cysteine synthetase (0.5 and 1 mM l-carnitine), was significantly increased. In addition, pre-treatment of l-carnitine in GCO cells exposed to 2.5 mM H2O2 significantly increased the mRNA expression of copper, zinc superoxide dismutase, catalase (0.5 mM l-carnitine), glutamate cysteine ligase catalytic subunit (0.1–1 mM) and glutathione peroxidase (0.1 mM l-carnitine). In conclusion, l-carnitine promotes GCO cell growth and improves antioxidant function, it plays a protective role against oxidative stress induced by H2O2 in GCO cells, and the appropriate supplemental amount of l-carnitine is 0.1–1 mM.