Nephrotoxicity of gentamicin (GM) has been suggested to be mediated by the generation of reduced oxygen metabolites. The present study investigated the possible protective role of the free radical scavenger dimethyl sulfoxide (DMSO) on some indices of GM nephrotoxicity in rats. The antibiotic was injected intramuscularly (i.m.) at a dose of loo mg/kg for six consecutive days, either with or without treatment with DMSO (12.5%, 25% or 50% in saline) at an intraperitoneal (i.p.) dose of 2 ml/kg 4 days before GM, and concomitantly with GM treatment thereafter. DMSO (25% in saline) was also given as above to rats treated with GM at i.m. doses of 25, 50 or 100 mg/kg for six consecutive days. GM caused dose-dependent significant increases in the concentrations of urea and creatinine in plasma, and in thiobarbituric acid reactive substances (TBARS) level in the kidney cortex and also caused significant decreases in the concentrations of reduced glutathione (GSH) and superoxide dismutase (SOD) activity. In GM-treated rats, DMSO dose-dependently lowered the elevated plasma urea and creatinine concentrations, and the rise in cortical TBARS. It also restored the levels of GSH and SOD activity to near normal. DMSO (25%) was effective in completely preventing the development of signs of nephrotoxicity of G (50 mg/kg). Treatment of the rats with DMSO alone, at any of the above doses, did not alter significantly any of the renal or hepatic function tests studied, and did not appear to adversely affect the kidney or liver histology. However, the efficacy and safety of DMSO require further studies. It is suggested that DMSO has potential protective effect against GM nephrotoxicity in rats.
