L‐carnitine exerts a cytoprotective effect against H 2 O 2 ‐induced oxidative stress in the fathead minnow muscle cell line

This study was conducted to investigate the protective effect of L‐carnitine ( LC ) against H 2 O 2 ‐induced oxidative stress in the fathead minnow muscle cell line ( FHM ). The FHM cells were stimulated with 1 mM H 2 O 2 for 1 h after LC pre‐treatment, and the cell viability and the activity and mRNA relative expression of antioxidant enzyme were measured to assess the antioxidant properties of LC . The results showed that the toxic effect of H 2 O 2 on the viability of FHM cells was both dose‐ and time‐dependent. Furthermore, the viability of the 0.01–1 LC mM groups was significantly higher than those of the 1 mM H 2 O 2 group. L‐carnitine protected the cells from H 2 O 2 ‐induced oxidative damage, which was demonstrated by a significant reduction in the malondialdehyde and reactive oxygen species levels and increases in the intracellular total glutathione levels and the activities of total superoxide dismutase, catalase, glutathione peroxidase ( GP x) and gamma‐glutamyl‐cysteine synthetase (γ‐ GCS ) in FHM cells pre‐treated with LC for 6 h compared with the 1 mM H 2 O 2 group. In addition, the mRNA relative expression levels of the γ‐ GCS catalytic subunit and nuclear factor nuclear factor erythroid 2‐related factor 2 were significantly higher than those of the 1 mM H 2 O 2 group. It could be concluded that LC exerts a beneficial antioxidant effect against oxidative stress induced by H 2 O 2 in FHM cells and that the appropriate treatment is 0.1–1 mM for 6 h in this study.