Further aspects of muscular dystrophy in mdx mice

The histopathological aspects of leg muscles in young, adult and old mdx mice were compared. Before 1 yr of age, the mutant showed a vigorous regeneration, following the fibre necrosis, which led to hypertrophic muscles. Hypertrophy resulted from a mixture of hypertrophic and small fibres but not from fibrosis. From the age of 15 months, the muscles progressively atrophied and the fibres were atrophic or split. An important degree of fibrosis occurred particularly in soleus and plantaris muscles. These aspects in old mdx mice are similar to those described in other dystrophinopathies in animals and humans.