Specific increase of genetic expression of parvalbumin in fast skeletal muscles of mdx mice

Parvalbumin mRNA was assayed by Northern blot analysis in muscles from normal and dystropic (mdx) mice. Its content was found to be specifically higher in mdx fast muscles than in control preparations. This suggests an increased expression of the protein in dystrophin-lacking fast fibres. A possible role in calcium homeostasis is discussed

Expression of truncated utrophin leads to major functional improvements in dystrophin-deficient muscles of mice

Dystrophin-deficient mice (mdx) expressing a truncated (trc) utrophin transgene show amelioration of the dystrophic phenotype. Here we report a multifunctional study demonstrating that trcutrophin expression leads to major improvements of the mechanical performance of muscle (that is, force development, mechanical resistance to forced lengthenings and maximal spontaneous activity) and of the maintenance of the intracellular calcium homeostasis. These are two essential functions of muscle fibers, known to be impaired in mdx mouse muscles and Duchenne muscular dystrophy (DMD) patients. Our results bring strong support to the hypothesis that muscle wasting in dystrophin-deficient DMD patients could be prevented by upregulation of utrophin