Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We evaluated the effects of long-term administration of deflazacort (DFZ) on the progression of myocardial fibrosis in mdx mice. Mdx mice (6 months old) were treated with DFZ for 15 months. Myocardial fibrosis (MF) was evaluated by histomorphometric methods, and treated and untreated mdx mice of the same age (21 months) were compared. DFZ significantly decreased MF We conclude that long-term therapy with DFZ is effective in slowing down the progression of fibrosis in the dystrophin-deficient heart. Muscle Nerve 40: 466-468, 2009403466468Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [95/6110-2, 01/00570-4, 04/15526-9]CNPq [301386/07-2, 306689/06-5, 474708/06-3]