DIETARY MAGNESIUM-DEFICIENCY IN RATS ENHANCES FREE-RADICAL PRODUCTIONIN SKELETAL-MUSCLE

Recent studies suggest that free radicals may be involved in tissue in juries induced by magnesium deficiency. The aim of the present study w as to assess the effect of magnesium deficiency on free radical produc tion of skeletal muscle tissue. Male Wistar rats were pair-fed from we aning for 12 d either control or Mg-deficient diets containing 960 or 40 mg magnesium/kg diet, respectively. In the Mg-deficient rats, hypom agnesemia was accompanied by significantly lower magnesium and greater calcium concentrations in skeletal muscle tissue. Electron microscopy of skeletal muscle tissue revealed ultrastructural changes, including swelling mitochondria and disorganization of the sarcoplasmic reticul um network. Using the spin-trapping technique, we showed that signific antly more hydroxyl radicals were generated in muscle homogenates of M g-deficient rats. Moreover, the amount of spin trap adducts was increa sed in the presence of exogenous iron in both groups. In agreement wit h these observations, a greater concentration of thiobarbituric acid-r eactive substances and a lower concentration of thiol groups were foun d in skeletal muscle of the Mg-deficient group compared with controls. These results strongly support the hypothesis that free radical-media ted injury could contribute to skeletal muscle lesions resulting from magnesium deficiency.