Effects of green tea catechins and exercise on age-related muscle atrophy and satellite cell functions in a mouse model of sarcopenia

Sarcopenia negatively affects the quality of life and health of older individuals. Physical exercise is a standard treatment for sarcopenia. Recently, the potential benefits of green tea catechins (GTCs) in sarcopenia have gained considerable attention. In this study, we investigated the effects of a combination of GTCs and physical exercise on the symptoms and pathologies of sarcopenia using male senescence-accelerated mouse prone 8 (SAMP8). These mice were divided into four groups: control, GTCs, exercise (Ex), and GTCs + Ex. GTC-fed mice were fed a diet containing 0.33 % GTCs. The mice were subjected to exercise training (voluntary wheel running) for 12 weeks, from 5 to 8 months of age, and grip strength and gastrocnemius muscle alterations were investigated. SAMP8 mice exhibited symptoms and pathologies of sarcopenia, including loss of muscle mass, decreased grip strength, reduced mitochondrial capacity, increased oxidative stress, reduced number of satellite cells, and an increased ratio of 5-bromo-2′-deoxyuridine (BrdU)-positive nuclei located within the muscle cells in the aged muscle. The GTCs and/or Ex groups showed improved symptoms and pathologies of sarcopenia. In addition, the GTCs + Ex group exhibited enhanced mitochondrial capacity, myogenic differentiation, and maturation in aged skeletal muscle than that observed in the GTCs group. Our findings suggested that GTCs and/or Ex are effective in ameliorating several age-related changes in muscle morphology and function. Notably, GTCs intake, together with habitual exercise, may enhance the beneficial effects on the symptoms and pathologies of sarcopenia in aged muscle.