The Acute Satellite Cell Response and Skeletal Muscle Hypertrophy following Resistance Training

• Published in: PloS one Vol. 9; no. 10; p. e109739
• Main Authors: Bellamy, Leeann M., Joanisse, Sophie, Grubb, Amanda, Mitchell, Cameron J., McKay, Bryon R., Phillips, Stuart M., Baker, Steven, Parise, Gianni
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.10.2014; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Biology and Life Sciences; Cell Cycle; Cell Proliferation; Fitness training programs; Gene expression; Humans; Hypertrophy; Kinesiology; Magnetic resonance imaging; Male; Males; Medicine and Health Sciences; Muscle Fibers, Slow-Twitch - physiology; Muscle, Skeletal - cytology; Muscle, Skeletal - physiology; Muscles; Musculoskeletal system; Myostatin - metabolism; PAX7 Transcription Factor - genetics; PAX7 Transcription Factor - metabolism; Physical training; Quadriceps muscle; Resistance Training; Rodents; Satellite Cells, Skeletal Muscle - physiology; Skeletal muscle; Stem cells; Strength training; Training; Weightlifting; Young Adult; Ontario Canada; Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0109739

The extent of skeletal muscle hypertrophy in response to resistance training is highly variable in humans. The main objective of this study was to explain the nature of this variability. More specifically, we focused on the myogenic stem cell population, the satellite cell (SC) as a potential mediator of hypertrophy. Twenty-three males (aged 18-35 yrs) participated in 16 wk of progressive, whole body resistance training, resulting in changes of 7.9±1.6% (range of -1.9-24.7%) and 21.0±4.0% (range of -7.0 to 51.7%) in quadriceps volume and myofibre cross-sectional area (CSA), respectively. The SC response to a single bout of resistance exercise (80% 1RM), analyzed via immunofluorescent staining resulted in an expansion of type II fibre associated SC 72 h following exercise (pre: 11.3±0.9; 72 h: 14.8±1.4 SC/type II fibre; p<0.05). Training resulted in an expansion of the SC pool associated with type I (pre: 10.7±1.1; post: 12.1±1.2 SC/type I fibre; p<0.05) and type II fibres (pre: 11.3±0.9; post: 13.0±1.2 SC/type II fibre; p<0.05). Analysis of individual SC responses revealed a correlation between the relative change in type I associated SC 24 to 72 hours following an acute bout of resistance exercise and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.566, p = 0.012) and the relative change in type II associated SC following 16 weeks of resistance training and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.493, p = 0.027). Our results suggest that the SC response to resistance exercise is related to the extent of muscular hypertrophy induced by training.