Propranolol reduces cardiomyopathic injury induced by magnesium deficiency

We have previously established a link between magnesium-deficiency-induced cardiomyopathy and free radical injury. In the present study, golden Syrian male hamsters were placed on either magnesium-deficient or magnesium-supplemented diets. Animals from each group received either d,l-propranolol or d-propranolol (the non-beta-blocking form). After 14 days, the animals were sacrificed and their hearts isolated for morphological and morphometric analyses. Hematoxylin/eosin-stained sections were examined by a computer image analysis system for a morphometric determination of the severity of myocardial injury. Propranolol reduced both the density of lesions, from 0.32 to 0.06 lesions/mm2 (p < 0.01), and the area fraction of lesions, from 9.8 x 10(-4) to 2.5 x 10(-4) lesion area/mm2 (p < 0.01). In addition, d-propranolol was virtually equipotent to d,l-propranolol, indicating that part of the protective effect of propranolol, in this model, was attributable to its antioxidant properties.