Preventive Effect of Standardized <i>Lespedeza cuneata</i> Extract on Dexamethasone-Induced Muscle Atrophy in C57BL/6N Mice

Muscle atrophy, characterized by a decline in muscle mass and function, results from an imbalance between protein synthesis and degradation. This study explored the effects of standardized <i>Lespedeza cuneata</i> extract (LCE) on dexamethasone (DEX)-induced muscle atrophy. The mice were orally administered LCE for 17 days. Starting on day 7 of oral administration, DEX was intraperitoneally injected into mice daily for 10 days to induce muscle atrophy. LCE treatment significantly improved grip strength by 22.27% and 33.16% and increased muscle volume by 17.47% and 23.00% at doses of 250 and 500 mg/kg/day, respectively, compared with the DEX group, and also markedly restored hind limb muscle weight. At the molecular level, LCE decreased the mRNA expression of myostatin, muscle ring finger1, and muscle atrophy F-box, which are involved in proteolysis, by inhibiting forkhead box O3a translocation. Furthermore, LCE activated the mammalian target of rapamycin pathway and upregulated myogenesis-related genes via the phosphoinositide 3-kinase/Akt pathway. It also reduced nuclear factor kappa B-mediated inflammatory cytokines, including tumor necrosis factor alpha and interleukin-6. Thus, LCE may serve as a functional food ingredient that prevents muscle atrophy.