Gender differences in contractile and passive properties of mdx extensor digitorum longus muscle

Duchenne muscular dystrophy (DMD) is a severe, muscle-wasting disease caused by mutations in the dystrophin gene. The mdx mouse is the first and perhaps the most commonly used animal model for study of DMD. Both male and female mdx mice are used. However, it is not completely clear whether gender influences contraction and the passive mechanical properties of mdx skeletal muscle.

We compared isometric tetanic forces and passive forces of the extensor digitorum longus muscle between male and female mdx mice.

At age 6 months, female mdx mice showed better-preserved specific tetanic force. Interestingly, at 20 months of age, female mdx muscle appeared stiffer.

Our results suggest that gender may profoundly influence physiological measurement outcomes in mdx mice.