Xenogeneic transplantation of mitochondria induces muscle regeneration in an in vivo rat model of dexamethasone-induced atrophy.

Muscle atrophy significantly impairs health and quality of life; however, there is still no cure. Recently, the possibility of regeneration in muscle atrophic cells was suggested through mitochondrial transfer. Therefore, we attempted to prove the efficacy of mitochondrial transplantation in animal models. To this end, we prepared intact mitochondria from umbilical cord-derived mesenchymal stem cells maintaining their membrane potential. To examine the efficacy of mitochondrial transplantation on muscle regeneration, we measured muscle mass, cross-sectional area of muscle fiber, and changes in muscle-specific protein. In addition, changes in the signaling mechanisms related to muscle atrophy were evaluated. As a result, in mitochondrial transplantation, the muscle mass increased by 1.5-fold and the lactate concentration decreased by 2.5-fold at 1 week in dexamethasone-induced atrophic muscles. In addition, a 2.3-fold increase in the expression of desmin protein, a muscle regeneration marker, showed a significant recovery in MT 5 µg group. Importantly, the muscle-specific ubiquitin E3-ligases MAFbx and MuRF-1 were significantly decreased through AMPK-mediated Akt-FoxO signaling pathway by mitochondrial transplantation compared with the saline group, reaching a level similar to that in the control. Based on these results, mitochondrial transplantation may have therapeutic applications in the treatment of atrophic muscle disorders.