Fermented Antler Recovers Stamina, Muscle Strength and Muscle Mass in Middle-Aged Mice

In a previous study, we found that Lactobacillus curvatus HY7602-fermented antler (FA) improved exercise endurance by increasement of muscle mass and strength in a young mouse model. In this study, we investigated the effect of FA on recovery of muscle mass and strength in aging-induced muscle loss. We have used a middle-aged model in which muscle decline begins in many mammalian species. All mice performed treadmill exercise and forced swimming, and measured muscle grip strength. Then, calf muscle weight and histological analysis, blood biomarker and gene expression in soleus muscle tissue were measured. Muscle strength and forced swimming time were significantly increased in the FA-intake groups compared to controls. The levels of muscle and liver damage-related indicators (ATL, ALP, LDH and CK) and muscle endurance, fatigue and exercise performance-related indicators (lactate and creatinine) were significantly improved by FA supplementation. In addition, FA regulates genes related to muscle protein degradation (Atrogin-1 and MuRF1) and muscle fiber synthesis (MyoD and Myf5), resulting in increased muscle mass, and fiber diameter and area values. The Bax/Bcl-2 ratio, related to apoptosis in skeletal muscle was significantly decreased. These results demonstrate that FA improves exercise performance with ameliorating blood biomarkers and also increases muscle mass and muscle strength by inhibiting muscle proteolysis and promoting muscle synthesis in a middle-aged mouse.