Sublethal Toxicity of Thiamethoxam Insecticide in Albino Mice: Biochemical, Oxidative Damage and Histopathological Evaluations

Abstract

The Neonicotinoid insecticides are presently used in great amounts, but this can be a problem when the possible risks of occupational and environmental contamination are considered. The objective of this study was to investigate the potential adverse effects of sublethal doses of Thiamethoxam insecticide on serum biochemical, oxidative stress and histological alterations in male albino mice via 28-day repeated-dose oral toxicity study. The possible ameliorative effect of selenium plus vitamin E against the harmful effects of Thiamethoxam was also investigated. Mice in Thiamethoxam-treated groups received three sublethal doses (6, 12, and 30 mg/kg b.w./day). Animals in another group were orally co-administered selenium + vitamin E with the higher dose of insecticide. The results showed that Thiamethoxam significantly (p < 0.05) increased cholesterol levels and liver enzyme activities, in dose-dependent manner, compared to those of the control group. Levels of creatinine were not significantly changed, whereas uric acid increased at high doses. The oxidative stress parameters were significantly increased in association with decrease in total antioxidants level. The histological analysis revealed that the higher dose induced various alterations in tissues of vital organs, i.e. liver, kidney, lung and testes. Interestingly, the ameliorative effect of selenium + vitamin E in restoring the oxidative stress parameters was reflected by reducing severity of histopathological lesions. In conclusion, it appears that the sublethal dose < 6.0 mg/kg b.w./day, in repeated dose 28-day oral toxicity study, in male albino mice may be considered as No-Observed-Adverse-Effect-Level (NOAEL) of Thiamethoxam. Additionally, the antioxidant selenium, in mixture with vitamin E, showed an ameliorative effect against Thiamethoxam-induced toxicity.