The ameliorative effect of cysteine prodrug L-2-oxothiazolidine-4-carboxylic acid on cisplatin-induced nephrotoxicity in rats

Pathogenesis of nephrotoxicity of the synthetic anticancer drug cisplatin (CP) involves generation of reactive oxygen species and free radicals in the kidney cortex, and cysteine prodrug L-2-oxothiazolidine-4-carboxylic acid (OTC) has been confirmed to have a strong antioxidant action. Therefore, in the present work, we aimed at testing the possible protective or palliative effect of OTC on CP nephrotoxicity in rats. OTC was given at an oral dose of 150 mg/kg/day for 7 days. On day 7, some of these rats were given a single intraperitoneal injection of CP (or vehicle) at a dose of 6 mg/kg. Rats were killed, blood and urine samples were collected, and the kidneys were removed 6 days after CP treatment. Nephrotoxicity was evaluated histopathologically by light microscopy, and biochemically by measuring the concentrations of creatinine and urea in serum, reduced glutathione (GSH) concentration and superoxide dismutase (SOD) activity in renal cortex, and by urinalyses. CP significantly increased the concentrations of urea and creatinine (P < 0.05) by about 128% and 170% respectively. CP treatment reduced cortical GSH concentration by about 34% (P < 0.05), and the activity of SOD by about 28% (P < 0.05). CP treatment significantly increased urine volume and N-acetyl-beta-D-glucosaminidase (NAG) activity, and significantly decreased osmolality and protein concentrations. OTC significantly mitigated all these effects. Sections from saline- and OTC-treated rats showed apparently normal proximal tubules. However, kidneys of CP-treated rats had a moderate degree of necrosis. This appeared to be lessened when CP was given simultaneously with OTC. The concentration of CP in the cortical tissues was not significantly altered by OTC treatment. The results suggested that OTC had ameliorated the histopathological and biochemical indices of nephrotoxicity in rats. Pending further pharmacological and toxicological studies, OTC may potentially be useful as a nephroprotective agent.