Exercise training improves adipocyte accumulation and muscle fibrosis by TGF-β1 and α-SMA reduction after botulinum toxin type A administration in mice
Abstract Background: We aimed to investigate the effect of treadmill exercise on functional recovery of the murine gastrocnemius muscle and nerve after botulinum toxin type A (BoNT-A) administration. Methods: After the injection of 0.5 units of BoNT-A into the gastrocnemius muscle of ICR mice, treadmill exercise was conducted for a 6-week period, after which the muscle volume, weight, and sciatic functional index (SFI) was determined and a nerve conduction study (NCS) and histological evaluation were performed. Results: After exercise, there was no change in the gastrocnemius weight and volume, but NCS and SFI increased. Exercise prevented induced adipocyte accumulation and muscle fibrosis. Moreover, transforming growth factor-β1 and α-smooth muscle actin expressions decreased and CD34, brain-derived neurotrophic factor, and synaptosomal nerve-associated protein 25 expressions increased when treadmill exercise was performed after BoNT-A administration. Conclusions: Exercise can effectively recover the nerve function and would aid in muscle function recovery by preventing fat cell accumulation and muscle fibrosis after BoNT-A administration.