Revitalizing Muscle Repair: Hyaluronan Preserves Mitochondrial Architecture and Promotes Myogenesis Under...

Hyaluronic acid (HA), a major component of the glycome and a non-sulfated glycosaminoglycan, plays a crucial role in regulating stem cell behavior and function, thereby supporting skeletal muscle repair under inflammatory conditions. In this study, we investigated the effects of a mixture of HA fractions with different molecular weights (M-HA; 2-1000 kDa) on the repair capacity and myogenic potential of C2C12 murine myoblasts exposed to inflammatory stimuli. C2C12 cells were cultured, induced to differentiate, and treated with M-HA (1 mg/mL) under either physiological or inflammatory conditions (LPS, 10 µg/mL; IL-1β, 20 ng/mL). M-HA exhibited no cytotoxic effects, even at the highest concentration tested (1.0 mg/mL), and significantly enhanced scratch wound closure. Moreover, M-HA improved the myogenic index at day 5 of differentiation, promoted the expression of myogenic markers, preserved myosin heavy chain (MHC) levels under inflammatory stress, and reduced the expression of autophagy-related genes. Ultrastructural analyses revealed that untreated myotubes displayed swollen mitochondria, disrupted cristae architecture, and numerous autophagic vacuoles, whereas M-HA-treated cells exhibited well-preserved mitochondrial morphology, intact cristae organization, reduced cytoplasmic damage, and maintained myofibrillar structure. Taken together, the functional, molecular, and ultrastructural findings demonstrate that M-HA protects myoblasts from inflammation-induced cellular damage and supports their regenerative capacity. These results underscore the potential of glycomics-based strategies to enhance myogenic differentiation and promote skeletal muscle regeneration in inflammatory microenvironments.