Vibration acceleration enhances proliferation, migration, and maturation of C2C12 cells and promotes regeneration of muscle injury in male rats

Vibration acceleration (VA) using a whole-body vibration device is beneficial for skeletal muscles. However, its effect at the cellular level remains unclear. We aimed to investigate the effects of VA on muscles in vitro and in vivo using the C2C12 mouse myoblast cell line and cardiotoxin-induced injury in male rat soleus muscles. Cell proliferation was evaluated using the WST/CCK-8 assay and proportion of Ki-67 positive cells. Cell migration was assessed using wound-healing assay. Cell differentiation was examined by the maturation index in immunostained cultured myotubes and real-time polymerase chain reaction. Regeneration of soleus muscle in rats was assessed by recruitment of satellite cells, cross-sectional area of regenerated muscle fibers, number of centrally nucleated fibers, and conversion of regenerated muscle from fast- to slow-twitch. VA at 30 Hz with low amplitude for 10 min promoted C2C12 cell proliferation, migration, and myotube maturation, without promoting expression of genes related to differentiation. VA significantly increased Pax7-stained satellite cells and centrally nucleated fibers in injured soleus muscles on Day 7 and promoted conversion of fast- to slow-twitch muscle fibers with an increase in the mean cross-sectional area of regenerated muscle fibers on Day 14. VA enhanced the proliferation, migration, and maturation of C2C12 myoblasts and regeneration of injured rat muscles.