Dystrophin expression following the transplantation of normal muscle precursor cells protects mdx muscle from contraction-induced damage.

Duchenne muscular dystrophy (DMD) is the most frequent muscular dystrophy. Currently, there is no cure for the disease. The transplantation of muscle precursor cells (MPCs) is one of the possible treatments, because it can restore the expression of dystrophin in DMD muscles. In this study, we investigated the effects of myoblasts injected with cardiotoxin on the contractile properties and resistance to eccentric contractions of transplanted and nontransplanted muscles. We used the extensor digitorum longus (EDL) as a model for our study. We conclude that the sole presence of dystrophin in a high percentage of muscle fibers is not sufficient by itself to increase the absolute or the specific force in the EDL of transplanted mdx muscle. This lack of strength increase may be due to the extensive damage that was produced by the cardiotoxin, which was coinjected with the myoblasts. However, the dystrophin presence is sufficient to protect muscle from eccentric damage as indicated by the force drop results.