In continuation of my update on Tamoxifen
  Using the mdx5Cv mouse model of DMD, investigators found that  tamoxifen, given orally for more than a year, "caused remarkable  improvements of muscle force and of diaphragm and cardiac structure,"  according to lead author Olivier M. Dorchies, PhD, of the Department of  Pharmacology, Geneva-Lausanne School of Pharmaceutical Sciences of the  University of Geneva and University of Lausanne. For instance, in the  heart, fibrosis  was diminished by approximately 50%. In the diaphragm, the muscle of  the dystrophic mouse thought to be most like that of human DMD,  tamoxifen reduced fibrosis while increasing thickness as well as the  number and average diameter of muscle fibers. The net effect was that  tamoxifen raised the amount of contractile tissue available for  respiration by 72%.
  Patients with DMD show muscle degeneration, and their muscle fibers  become abnormally susceptible to stress. In this animal study, tamoxifen  improved the structure of leg muscles, slowed muscle contraction,  increased overall muscle function, and made leg muscles more resistant  to repetitive stimulation and fatigue. In fact, tamoxifen  rendered dystrophic muscles even stronger than those of non-dystrophic  control mice. "Our findings of a slower rate of contraction and an  enhanced resistance to fatigue in muscles from tamoxifen-treated  dystrophic mice are of significance for the pathophysiology of muscular  dystrophy," say the authors.
More : http://www.journals.elsevierhealth.com/periodicals/ajpa/article/S0002-9440%2811%2901061-3/abstract