Abstract: Objective: To explore the protective effect and potential mechanism ofβ-casomorphin5 (β-CM5) against hydrogen peroxide (H2O2)-induced oxidative damage in C2C12 cells. Methods: MTT method was used to determine the effect ofβ-CM5 on cell viability within 72 h and to screen the safe dose. Meanwhile, the effect of H2O2 with various concentrations on cell viability was also evaluated. In addition, the activities of superoxidedismutase (SOD) and lactate dehydrogenase (LDH) in medium were determined. Results: Compared with the control group, the values of MTT inβ-CM5 groups with various concentrations did not exhibit an obvious difference. In contrast, a significant decrease in MTT values of C2C12 cells was observed after 1 h of treatment with 0.25 mmol/L H2O2 (P＜0.01); Compared with the oxidative damage group, MTT value in theβ-CM5 pre-protection group was significantly higher (P＜0.05), while MTT value in theβ-CM5 treatment group had no significant difference when compared to the oxidative damage group. Compared with the oxidative damage group, the activity of SOD inβ-CM5 pre-protection group was significantly increased (P＜0.05), while the activity of LDH was significantly decreased (P＜0.05). Conclusion:β-CM5 has a strong antioxidant and pre-protective effect on H2O2-induced damage of C2C12 cells. The mechanism may be related to the increased activity of antioxidant enzymes and maintenance of cell integrality.

Key words: β-casomorphin5, C2C12 cell, hydrogen peroxide, superoxidedismutase (SOD), lactate dehydrogenase (LDH)