Low-amplitude high frequency vibration down- regulates myostatin and atrogin-1 expression, two components of the atrophy pathway in muscle cells Gabriele Ceccarelli 1,2 *, Laura Benedetti 1,2 , Daniela Galli 1,2 , Deborah Prè 2,3 , Giulia Silvani 1,2 , Nicola Crosetto 4 , Giovanni Magenes 2,3 and Maria Gabriella Cusella De Angelis 1,2 1 Dipartimento di Medicina Sperimentale, University of Pavia, Italy 2 Centro di Ingegneria Tissutale, University of Pavia, Italy 3 Dipartimento di Informatica e Sistemistica, University of Pavia, Italy 4 The van Oudenaarden Systems Biology Lab, Massachusetts Institute of Technology, USA Abstract Whole body vibration (WBV) is a very widespread mechanical stimulus used in physical therapy, rehabilitation and fitness centres. It has been demonstrated that vibration induces improvements in muscular strength and performance and increases bone density. We investigated the effects of low- amplitude, high frequency vibration (HFV) at the cellular and tissue levels in muscle. We developed a system to produce vibrations adapted to test several parameters in vitro and in vivo. For in vivo experiments, we used newborn CD1 wild-type mice, for in vitro experiments, we isolated satellite cells from 6-day-old CD1 mice, while for proliferation studies, we used murine cell lines. Animals and cells were treated with high frequency vibration at 30 Hz. We analyzed the effects of mechanical stimulation on muscle hypertrophy/atrophy pathways, fusion enhancement of myoblast cells and modifications in the proliferation rate of cells. Results demonstrated that mechanical vibration strongly down-regulates atrophy genes both in vivo and in vitro. The in vitro experiments indicated that mechanical stimulation promotes fusion of satellite cells treated directly in culture compared to controls. Finally, proliferation experiments indicated that stimulated cells had a decreased growth rate compared to controls. We concluded that vibration treatment at 30 Hz is effective in suppressing the atrophy pathway both in vivo and in vitro and enhances fusion of satellite muscle cells. Copyright © 2012 John Wiley & Sons, Ltd. Received 20 July 2011; Revised 18 January 2012; Accepted 4 April 2012 Keywords high frequency vibration; muscle tissue; hypertrophy/atrophy pathways; satellite cells; cell fusion 1. Introduction Recently, mechanical vibration has been used in clinical therapy and sports training to enhance performance and improve motor control (Nordlund and Thorstensson, 2007; Tihanyi et al., 2007; Von Stengel et al., 2010). Nevertheless, results remain controversial, since those studies only addressed systemic effects while effects at the cellular and tissue levels remain poorly understood. Over the past twenty years, several studies have attempted to analyze vibration stimuli effects on cells and tissues. In particular, studies on mechanical stimulation of the musculoskeletal system have been driven by Bosco and co-workers (Cardinale and Bosco, 2003) who created the well-known “vibrating platforms”, which are widespread in fitness and rehabilitation centres. Bosco was the first to prove that each person has his own muscle frequency. In fact, the human body is designed to absorb vertical vibrations better due to the effects of gravity. Results in athletes treated with a vibrating platform like the Galileo 2000 have been encouraging: subjects showed remarkable and statistically significant enhancements in average velocity (AV), average force (AF) and average power (AP) (Cardinale and Bosco, 2003; Bosco et al., 1999a, 1999b; Fernandez-Rio et al., 2010). Currently, there are many whole body vibration machines available that vary in quality, design, specifications and manufacturing materials. *Correspondence to: G. Ceccarelli, Dipartimento di Medicina Sperimentale, University of Pavia, Italy. E-mail: gabry_06@yahoo.it Copyright © 2012 John Wiley & Sons, Ltd. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE RESEARCH ARTICLE J Tissue Eng Regen Med (2012) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/term.1533