Force impairment in calpain 3-deficient mice is not correlated with mechanical disruption

• Published in: Muscle & nerve 2003-05, Vol.27 (5), p.616-623
• Main Authors: Fougerousse, Françoise, Gonin, Patrick, Durand, Muriel, Richard, Isabelle, Raymackers, Jean-Marc
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; calpain; Calpain - genetics; Calpain - metabolism; Disease Models, Animal; Diseases of striated muscles. Neuromuscular diseases; Electric Impedance; Female; Medical sciences; Mice; mice knockout; Mice, Mutant Strains; muscle contraction; Muscle Contraction - physiology; Muscle Fibers, Fast-Twitch - metabolism; Muscle Fibers, Slow-Twitch - metabolism; Muscle Proteins; Muscle, Skeletal - cytology; Muscle, Skeletal - physiology; Muscular Dystrophies - genetics; Muscular Dystrophies - metabolism; Muscular Dystrophies - physiopathology; Neurology; neuromuscular disease; Phenotype; physiology
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.10368

Defects in human calpain 3 are responsible for limb‐girdle muscular dystrophy type 2A, an autosomal‐recessive disorder characterized mainly by late‐onset proximal muscular atrophy. A corresponding murine model has previously been generated by gene targeting. In this report, muscular activity of calpain 3–deficient (capn3−/−) mice was evaluated at different ages. Growth curves showed a progressive global muscular atrophy. Histological examination throughout the lifespan of mice confirmed the dystrophic lesions. Whole animal tests showed only a mild significant impairment of the forelimbs. Studies of the mechanical properties of selected isolated fast‐ and slow‐twitch muscles demonstrated that slow‐twitch muscles were significantly weaker in capn3−/− mice than in wild‐type mice. Three different tests showed that there was no membrane disruption, suggesting a nonmechanical etiology of capn3−/− mice dystrophy. These findings are consistent with a mechanism involving signaling systems. Muscle Nerve 27: 616–623, 2003