Prevention by 2‐Mercaptoethane Sulfonate and N‐Acetylcysteine of Renal Oxidative Damage in Rats Treated with Ferric Nitrilotriacetate

Ferric nitrilotriacetate (Fe‐NTA) is a renal toxicant and carcinogen in rats and mice. We found that its administration results in formation of 4‐hydroxy‐2‐nonenal (HNE) in the renal proximal tubule cells of rats, and 8‐hydroxydeoxyguanosine (8‐OHdG) adducts in their DNA, suggesting a role for oxidative stress. Since 2‐mercaptoethane sulfonate (MESNA) and N‐acetylcysteine (NAC), administered orally, have been shown to increase the kidney levels of free thiol groups, their influence on the renal toxicity and carcinogenicity induced by Fe‐NTA was examined in the present study. Male Wistar rats were intraperitoneally injected with Fe‐NTA (12 mg Fe/kg), and MESNA (100 mg/kg) or NAC (200 mg/kg) was given orally 1 h before and 1 h after this treatment. The animals were killed for tissue analyses 3 h after the Fe‐NTA exposure. In accord with our previous reports, HNE‐modified protein was detected in the proximal tubules of Fe‐NTA‐treated rats by means of immunohistochemistry. Likewise, levels of 8‐OHdG in the renal nuclear DNA, lipid peroxides as thiobarbituric acid‐reactive substances in the kidneys, and blood urea nitrogen and creatinine in the serum were significantly increased by the Fe‐NTA treatment. All of these changes were completely inhibited by oral administration of MESNA or NAC. These results suggest that both of these compounds can prevent the oxidative stress induced by Fe‐NTA.