The effects of muscular dystrophy, exercise and sActRIIB-Fc on molecular signature of skeletal muscle in mice. Mus musculus

To study the combined effect of myostatin/activin inhibition and exercise on muscle mass and pathophysiology, young mdx mice, a model for Duchenne Muscular Dystrophy, were injected with soluble activin receptor-Fc (sActRIIB-Fc) or placebo (PBS) 1x/week for a 7-week period, in combination with or without voluntary running. C57Bl/10ScSnJ mice injected with PBS acted as wildtype controls. Microarray expression analysis from skeletal muscle was performed using m. gastrocnemies as the sample. We found thatexercise or a combination of exercise and sActRIIB-Fc treatment is more effective in correcting gene expression profiles of dystrophic muscles than the sActRIIB-Fc treatment alone. We also identified several pathways and proteins that were affected by exercise and sActRIIB-Fc together or independently. Overall design: Total RNA obtained from gastrocnemius muscle of mdx mice divided into four groups: 1) control (injected with PBS, n=5), 2) runners (voluntary wheel running for 7 weeks, injected with PBS, n=5), 3) sActRIIB-Fc -treated (n=5), and 4) runners with sActRIIB-Fc-treatment (n=5). sActRIIB-Fc or PBS was injected intraperitoneally once a week with a 5-mg/kg dose of sActRIIB-Fc. In addition, wildtype mice served as healthy controls (n=4).