INVOLVEMENT OF FREE-RADICALS IN DUCHENNES AND BECKERS DISEASES

Duchenne's and Becker's muscular dystrophies are X-linked pathologies resulting from mutations of the gene codifying for dystrophin. The gen etic damage phenotypically involves a lesion in muscular fibers. Free radical production, coupled with oxygen metabolism, is associated with a degenerative state, and the active form of oxygen is present in man y nerve and muscle disorders. This study evaluated the link between th e clinical course of these dystrophies and changes in free radical pro duction and urinary malondialdehyde (MDA) concentration in healthy con trols, patients with dystrophic cardiomyopathy, and patients with Duch enne's and Becker's myopathy with or without cardiac involvement. MDA concentration and free radical production were evaluated at baseline a nd after 3 and 6 months of ubiquinone treatment (50 mg/d orally). At b aseline, MDA concentration was significantly increased in all groups c ompared with controls, except for patients with nondystrophic cardiomy opathy, indicating an increase of lipoperoxidation in the dystrophic d iseases. Ubiquinone treatment caused no significant changes compared w ith baseline. Thus, MDA production remains constant during the disease and is not affected by ubiquinone. Both at baseline and after treatme nt, the phagocytosis index, an indication of free radical production, decreased significantly compared with control values in all patients. Ubiquinone treatment did not modify this decrease. Free radicals are t hus involved in Duchenne's and Becker's dystrophies and are a noninvas ive marker of these diseases.