Exercise increases utrophin protein expression in the mdx mouse model of Duchenne muscular dystrophy.

INTRODUCTION Duchenne muscular dystrophy (DMD) is a lethal genetic disease caused by mutations in the dystrophin gene resulting in chronic muscle damage, muscle wasting, and premature death. Utrophin is a dystrophin protein homologue that increases dystrophic muscle function and reduces pathology. Currently, no treatments that increase utrophin protein expression exist. However, exercise increases utrophin mRNA expression in healthy humans. Therefore, the purpose was to determine whether exercise increases utrophin protein expression in dystrophic muscle. METHODS Utrophin protein was measured in the quadriceps and soleus muscles of mdx mice after 12 weeks of voluntary wheel running exercise or sedentary controls. Muscle pathology was measured in the quadriceps. RESULTS Exercise increased utrophin protein expression 334 ± 63% in the quadriceps relative to sedentary controls. Exercise increased central nuclei 4 ± 1% but not other measures of pathology. CONCLUSIONS Exercise may be an intervention that increases utrophin expression in patients with DMD.