Preventive Role of Muscle-Derived Estrogen in C₂C₁₂Myoblasts against Oxidative Damage

This article aims to investigate the effect of mechanical stretch on the production of endogenous E2 (estradiol) in mouse C2C12 myoblasts under a low estrogen culture environment and its potential antioxidant effects. In this study, the cells were divided into five groups: control group (C group), stretch group (15%, 0.5 Hz, 6 h), H2O2 group (400 μmol/L, 4 h), stretch + H2O2 group and aromatase inhibitor (200 μg/mL, 24 h) + stretch + H2O2 group. The low estrogen culture environment was created by using charcoal-stripped FBS and phenol red-free DMEM high-glucose medium. Changes in cell viability were detected by the CCK8 assay, while intracellular E2 levels were measured by the Elisa method. The activities of SOD, CAT, and GSH-Px were determined by the WST-1, am-monium molybdate, and colorimetric methods, respectively. MDA generation was measured using the TBA method. Western blot was performed to analyze changes in the expression of Akt/Nrf2/HO-1 proteins in the cells. Compared with the C group, the mechanical stretch group showed an increase in aromatase activity and protein expression (P<0.01) and an increase in intracellular E2 generation (P<0.01). The H2O2 group exhibited oxidative damage, manifested by a decrease in cell viability (P<0.01) and a downregulation of HO-1 protein expression (P<0.05). Compared with the H2O2 group, the mechanical stretch + H2O2 group showed an increase in cell viability (P<0.01), an elevation in SOD, CAT, and GSH-Px activity (P<0.01), a decrease in MDA production (P<0.01), and an upregulation of Akt phosphorylation and HO-1 protein expression (P<0.05). Compared with the mechanical stretch + H2O2 group, the aromatase inhibitor + mechanical stretch + H2O2 group showed a decrease in cell viability (P<0.01), a decrease in SOD, GSH-Px, and CAT activity (P<0.01), an increase in MDA content (P<0.01), and downregulation of Akt phosphorylation, Nrf2, and HO-1 protein expression (P<0.05). Under low estrogen conditions, appropriate mechanical stretch can promote the expression of aromatase and E2 generation in C2C12 myoblasts, increase cell viability, and upregulate Akt/Nrf2/HO-1 protein expression, providing specific preventation against oxidative damage to the cells.

CSTR: 32200.14.cjcb.2023.09.0006