Title : Effects of low dose imidacloprid exposure on pesticide levels and primary DNA damage in blood and brain of male wistar rats
Imidacloprid is a systemic pesticide used for crop protection and in the veterinary field that belongs to the group of the most widely used insecticides in the world - neonicotinoids. It acts selectively as an agonist on nicotinic acethylcholine receptors in insects. Due to its widespread use and detectable levels in the environment, imidacloprid can have adverse health effects in many species, including mammals. To assess the potential genotoxicity of imidacloprid, we investigated the effects of oral 28-day exposure to environmentally relevant doses of imidacloprid (0.06 mg/kg b. w./day, 0.8 mg/kg b. w./day and 2.25 mg/kg b. w./day) on pesticide levels and primary DNA damage in blood and brain of adult male Wistar rats. After the treatment, we applied the alkaline comet assay to determine primary DNA damage (based on tail intensity, i.e. DNA% in the comet’s tail) in leukocytes and brain cells. Levels of imidacloprid in plasma and brain tissue were measured using high performance liquid chromatography with a UV diode-array detector. The presence of imidacloprid in the plasma of all treated animals and in the brain of animals treated with two higher doses was revealed. We observed peripheral blood leukocytes damage at the lowest dose of imidacloprid and dose-dependent brain cells DNA damage. Oral 28-day exposure to low doses of imidacloprid in rats resulted in detectable levels of imidacloprid in plasma and brain tissue that directly induced DNA damage, particularly in brain tissue. Our results call for further investigations of adverse outcomes associated with environmental imidacloprid exposure, especially long-term exposure to environmentally relevant doses, using other sensitive biomarkers of effect.