title: Voluntary physical activity protects from susceptibility to skeletal muscle contraction-induced injury but worsens heart function in mdx mice.
abstract: It is well known that inactivity/activity influences skeletal muscle physiological characteristics. However, the effects of inactivity/activity on muscle weakness and increased susceptibility to muscle contraction-induced injury have not been extensively studied in mdx mice, a murine model of Duchenne muscular dystrophy with dystrophin deficiency. In the present study, we demonstrate that inactivity (ie, leg immobilization) worsened the muscle weakness and the susceptibility to contraction-induced injury in mdx mice. Inactivity also mimicked these two dystrophic features in wild-type mice. In contrast, we demonstrate that these parameters can be improved by activity (ie, voluntary wheel running) in mdx mice. Biochemical analyses indicate that the changes induced by inactivity/activity were not related to fiber-type transition but were associated with altered expression of different genes involved in fiber growth (GDF8), structure (Actg1), and calcium homeostasis (Stim1 and Jph1). However, activity reduced left ventricular function (ie, ejection and shortening fractions) in mdx, but not C57, mice. Altogether, our study suggests that muscle weakness and susceptibility to contraction-induced injury in dystrophic muscle could be attributable, at least in part, to inactivity. It also suggests that activity exerts a beneficial effect on dystrophic skeletal muscle but not on the heart.
authors: Institute of Myology, INSERM U974, CNRS UMR7215, UPMC UM76, Université Pierre et Marie Curie-Paris 6, Sorbonne Universities, Paris, France.
authors: Christophe
authors: C
authors: Hourdé
authors: Pierre
authors: P
authors: Joanne
authors: Fadia
authors: F
authors: Medja
authors: Nathalie
authors: N
authors: Mougenot
authors: Adeline
authors: A
authors: Jacquet
authors: Etienne
authors: E
authors: Mouisel
authors: Alice
authors: A
authors: Pannerec
authors: Stéphane
authors: S
authors: Hatem
authors: Gillian
authors: G
authors: Butler-Browne
authors: Onnik
authors: O
authors: Agbulut
authors: Arnaud
authors: A
authors: Ferry
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001835:Body Weight; D004198:Disease Susceptibility / Q000473:pathology*; D005786:Gene Expression Regulation; D006321:Heart / Q000503:physiopathology*; D006334:Heart Function Tests; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D009119:Muscle Contraction / Q000502:physiology*; D024510:Muscle Development / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D009137:Muscular Dystrophy, Animal / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size; D010084:Oxidation-Reduction; D010805:Physical Conditioning, Animal; D016276:Ventricular Function / Q000235:genetics
chemical_list: D015415:Biomarkers