Toxicological assessment of a commercial imidacloprid formulation: evidence of systemic, oxidative and genotoxic effects in rats.

Imidacloprid (IMI) is a neonicotinoid insecticide used in agriculture, domestic environments, and veterinary medicine. The objective of this study was to evaluate possible toxic effects of an IMI based commercial formulation on oxidative parameters, renal and mitochondrial functions and genotoxicity. Adult Wistar rats received oral doses of 1.5; 5 and 15mg/kg of an IMI suspension for 45 days. The 1.5mg/kg group showed a reduced polychromatic/normochromatic micronucleus ratio and increased polychromatic cells, indicating genotoxic damage. An increase in spleen lipoperoxidation and in the activity of the blood catalase were observed in the 5mg/kg IMI treated group. Increase in the activity of the hepatic mitochondrial respiratory chain complexes I-IV was observed in all groups. Histopathological analysis revealed alterations in the liver, kidneys and spleen at 5 and 15mg/kg. Although IMI presents selectivity for insects, our study demonstrated systemic alterations and genotoxicity in rats, suggesting possible toxicity in mammals.