Magnesium-deficient myocardium demonstrates an increased susceptibility to an in vivo oxidative stress.

Previous studies in our laboratory have indicated free radical participation in magnesium deficiency cardiomyopathy. In this study, we examined the capacity of the magnesium-deficient animals to withstand an in vivo oxidative stress. Syrian hamsters were placed on either magnesium-deficient diet or a magnesium-supplemented control diet. Animals from each group also received vitamin E. After 14 days some of animals were given the catecholamine isoprenaline; 2 days later the animals were killed. The severity of the isoprenaline-induced injury was assessed by a morphometric analysis. The isoprenaline-induced injury was dramatically increased in the magnesium-deficient animals. The addition of vitamin E reduced the severity of the injury by 81% in these animals, indicating that the injury process was primarily due to an oxidative mechanism. These data show that magnesium deficiency increases the susceptibility of the cardiovascular system to oxidative stress.