Improved contractile function of the mdx dystrophic mouse diaphragm muscle after insulin-like growth factor-I administration

Abstract

Limited knowledge exists regarding the efficacy of insulin-like growth factor I (IGF-I) administration as a therapeutic intervention for muscular dystrophies, although findings from other muscle pathology models suggest clinical potential. The diaphragm muscles of mdx mice (a model for Duchenne muscular dystrophy) were examined after 8 weeks of IGF-I administration (1 mg/kg s.c.) to test the hypothesis that IGF-I would improve the functional properties of dystrophic skeletal muscles. Force per cross-sectional area was ∼49% greater in the muscles of treated mdx mice (149.6 ± 9.6 kN/m2) compared with untreated mice (100.1 ± 4.6 kN/m2, P < 0.05), and maintenance of force over repeated maximal c..