Postnatal Exposure to A Low Dose of Imidacloprid: Oxidative Stress in Brain Without Affecting Learning and Behavior in Swiss Albino Mice

Abstract

The neurotoxic effects of exposure to low levels of the pesticide imidacloprid (IMI) and the effect of curcumin are of current interest when exposure occurs during early development. Male weanlings of Swiss albino mice (21 days old) were given 1 mg.kg-1 body weight (1/130 of LD50 and 2 mg.kg-1 body weight (1/65 of LD50) of imidacloprid and Curcumin (100 mg/kg body wt.) by oral gavage from postnatal day 21 to postnatal day 60. Young adult offspring were studied for behavioral parameters and learning ability using open field and Morris water maze. After completing the behavioral test, brains were processed for acetylcholine esterase activity and antioxidant enzyme estimation. The level of lipid peroxidation and activity of catalase, superoxide dismutase, and glutathione were assayed. In the present study, parameters such as locomotor activities and cognitive skills were not affected compared to lower doses of imidacloprid in the open field and Morris water test. However, activities and levels of antioxidant enzymes such as catalase and lipid peroxidation were found to be altered. In contrast, superoxide dismutase, acetylcholine esterase activity, and glutathione remained unchanged compared to the control. This suggests that subchronic exposure to low doses of IMI can lead to significant alterations in the enzymes of antioxidant protective systems such as catalase and lipid peroxidation. Co-treatment with curcumin was able to restore the activities of the affected enzymes in comparison with the control.

Keywords

• development period, imidacloprid, oxidative stress, swiss albino mice