Canine Adipose MSC-Derived Exosomes Ameliorate Skeletal Muscle Injury in Mice

Severe skeletal muscle injury in dogs can result in muscle atrophy, fibrotic remodeling, and fat accumulation, leading to skeletal muscle dysfunction and impaired quality of life. However, there is currently no effective treatment available. This study aims to investigate the potential of canine adipose mesenchymal stem cell-derived exosomes (cADMSC-Exos) as a novel acellular therapy for the repair of muscle atrophy and injury. cADMSCs and their derived exosomes were isolated and characterized. A dexamethasone-induced C2C12 myotube atrophy model was established to evaluate the effects of cADMSC-Exos on muscle atrophy by assessing myotube morphology and the expression of atrophy-related factors. Subsequently, a glycerol-induced mouse muscle injury model was constructed. Through histological analysis and Western blot, the efficacy and safety of cADMSC-Exos in vivo were systematically evaluated. Results indicated that cADMSC-Exos demonstrated significant anti-atrophic activity in both two models, ameliorating skeletal muscle atrophy and the upregulation of muscle RING finger 1 (MuRF1) and muscle atrophy F-box (Atrogin-1) (p < 0.05), consistent with morphological alterations. Moreover, cADMSC-Exos markedly alleviated fibrosis and fatty infiltration in injured muscle tissue (p < 0.0001). Overall, these findings indicate that cADMSC-Exos promote muscle repair and attenuate pathological remodeling by modulating the local microenvironment and protein expression, highlighting their potential as a therapeutic strategy for muscular disorders.