Nitrosative stress in rat spleen following subchronic exposure to aniline

Abstract

Molecular mechanisms of aniline-induced selective toxicity to the spleen is not well understood. Previously, we have shown that aniline exposure in rats leads to increased lipid peroxidation, protein oxidation and DNA oxidation, suggesting the role of oxidative stress in aniline-induced toxicity. The focus of the present study was to evaluate if nitosative stress also contributes to the splenic toxicity, by determining increased formation of nitrotyrosine (NT) and regulation of iNOS. Male SD rats were treated with 0.5 mmol/kg/day aniline via drinking water for 30 days (controls received drinking water only). An NT-specific ELISA showed a 334% increase in NT formation in the spleens of aniline-treated rats compared to the controls. Western blot analysis of the post-nuclear fractions of spleens from both aniline-treated and control animals showed nitrated proteins with molecular weights of 18, 26, 46, 55, 58 and 66 kDa. Furthermore, a comparison of the relative densities of the nitrated proteins showed stronger intensities for all nitrated proteins in the aniline-treated rats, prominent being 18, 46 and 66 kDa. The increased formation of nitrated proteins was associated with increased iNOS activity in the splenocytes (ELISA and Western blot analysis) from aniline-treated rats. Our data suggest that aniline-induced nitrosative stress could also be a contributory factor in the splenic toxicity of aniline.