Evaluating the impact of increasing vitamin C and E concentration on primary ovine satellite cells

Abstract

Skeletal muscle becomes meat through a series of biochemical processes post-harvest. Since sheep producers are typically paid based on carcass weight, a goal is to optimize skeletal muscle growth, as well as the yield and quality of the final meat product. Satellite cells are stem cell-like cells responsible for mammalian postnatal skeletal muscle growth capacity through myonuclear accretion. Satellite cells proliferate and then differentiate into myoblasts before fusing with existing myotubes. Inflammation, as well as free radicals, stimulate skeletal muscle growth. Antioxidants such as vitamins C and E combat unstable free radicals to maintain a healthy concentration to promote skeletal muscle growth. Despite potential involvement in sheep skeletal muscle growth, ideal concentrations of vitamin E and C for optimal skeletal muscle growth are unknown. The objective of this project is to determine if increasing concentrations of α-tocopherol or ascorbic acid affects the proliferation rates of primary ovine satellite cells (OSC) or protein synthesis rates of fused primary OSC. Primary OSC were isolated from the hind leg of 9-mo old commercial hair sheep wethers (n=8). For proliferation, cultures were grown to approximately 70% confluency, followed by treatment with 5% fetal bovine serum (FBS) or 5% FBS and concentrations of α-tocopherol (4.6 µM, 9.2 µM, or 13.8 µM) or ascorbic acid (8 µM, 16 µM, or 24 µM). Protein synthesis cultures were induced to differentiate at approximately 85% confluency and treated 48 h later with serum free media (SFM) or SFM and concentrations of α-tocopherol (4.6 µM, 9.2 µM, or 13.8 µM) or ascorbic acid (8 µM, 16 µM, or 24 µM). Proliferation rates were measured at 24 h post-treatment, and protein synthesis rates were measured at 6 h post treatment. Fused primary OSC protein synthesis rates linearly increased (P = 0.007) with increasing α-tocopherol concentrations. Increasing ascorbic acid treatment led to a linear increase (P = 0.05) of proliferation rates, while fused primary OSC treatment saw a linear (P = 0.08) and quadratic (P = 0.06) tendency for an increase in protein synthesis rates. These findings suggest that increasing vitamin C supplementation could increase myonuclear accretion potential, and increasing vitamin E and C supplementation could increase skeletal muscle growth.