Low-amplitude high frequency vibration down-regulates myostatin and atrogin-1 expression, two components of the atrophy pathway in muscle cells

Whole body vibration (WBV) is a mechanical stimuli very widespread in physical therapy, rehabilitation and in fitness centres. It has been demonstrated that vibration induces improvements in muscular strength and performance and increases bone density. In this study, we investigated the effects of low-amplitude, high frequency vibration (HFV) at cellular and tissue level in muscle tissue and, for this reason, we realized a system to produce vibrations with all the adaptations for “in vitro” and “in vivo” studies. For in vivo studies we used newborn mice CD1 wild-type, while, for in vitro analyses, we isolated satellite cells, the adult stem cells of muscle tissue, from 6-days-old CD1 mice and we additionally used murine cell lines for proliferation studies. Animals and cells were treated with high frequency vibration at 30 Hz. We analyzed the effects of the mechanical stimulation on muscle hypertrophy/atrophy pathway, in enhancing fusion of myoblast cells and in modifying proliferation rate of cells. Results demonstrate that mechanical vibration strongly down-regulates atrophy genes both in vivo and in vitro treated samples with respect to controls. In vitro studies seem to indicate that the mechanical stimulation promotes fusion of primary myoblasts of satellite cells treated directly in culture with respect to control ones. Results about proliferation rate of cells indicated that stimulated cells show a decreased grow rate than the control ones. Hence, we concluded that vibration treatment at 30 Hz is effective in suppressing atrophy pathway both in vivo and in vitro and the reduced of cell proliferation support the hypothesis that the vibration treatment promotes muscular differentiation.