Exposure to Polystyrene Nanoplastics Induces an Anxiolytic-Like Effect, Changes in Antipredator Defensive Response, and DNA Damage in Swiss Mice

Abstract

Thus, we aimed to evaluate whether exposure to polystyrene (PS) NPs at 6.5 ng/kg and 6500 ng/kg) alters the behavior of male Swiss mice. After 20-days of exposure, our data showed no effects of pollutants on the locomotor activity of the animals. However, we noticed an anxiolytic-like behavior and alterations in the antipredatory defensive response of mice exposed to PS NPs, when confronted with their predator potential (snake, Pantherophis guttatus ). Furthermore, such changes were associated with suppressing brain antioxidant activity, inferred by lower DPPH radical scavenging activity and reduced glutathione content. Also, we noticed that the treatments induced DNA damage, evaluated via a single-cell gel electrophoresis assay applied to circulating erythrocytes of the animals. However, we did not observe a dose-response effect for all biomarkers evaluated and the estimated accumulation of PS NPs in the brain. The values ​​of the integrated biomarker response index and the results of the principal component analysis and the hierarchical clustering analysis confirmed the similarity between the responses of animals exposed to different doses of PS NPs. Therefore, our study sheds light on how PS NPs can impact mammals and reinforce the ecotoxicological risk associated with the dispersion of these pollutants in natural environments.

Keywords: nanotoxicology, mammals, ecotoxicology, nanomaterials, Plastic pollution