Effect of magnesium diet in gentamicin-induced acute renal failure in rats

Clearance experiments were conducted with metabolic cages to determine the effect of dietary magnesium on gentamicin nephrotoxicity. Three groups of male Wistar rats were given low, medium- or high-magnesium diets. Following baseline clearances, gentamicin was administered by intramuscular injection (20 mg/kg). Additional clearances were performed 6 and 11 days after gentamicin administration. 24-hour clearances were also taken 8 days after gentamicin withdrawal. The present experiments demonstrated that high magnesium intake protected the kidney against injury induced by gentamicin. This reduction in nephrotoxicity was probably due to competition of binding between magnesium and gentamicin to the renal membrane. Histological examinations were also done in these animals. The results showed that the most severe changes were seen in rats receiving a low-magnesium diet. Rats given a high-magnesium diet showed the least toxic changes while rats receiving a medium-magnesium diet showed changes of intermediate severity. These observations complemented the results obtained from 24-hour clearances and indicate the protective effect of dietary magnesium on the development of acute renal failure following administration of gentamicin.