Polystyrene microplastics (PS-MPs) toxicity induced oxidative stress and intestinal injury in nematode Caenorhabditis elegans

To understand the toxicity and mechanism of polystyrene microplastics (PS-MPs) exposure, Caenorhabditis elegans (C. elegans) was exposed to various concentrations (0, 0.1, 1, 10, and 100 μg/L) of PS-MPs, and the levels physiological, biochemical, and molecular parameters were measured as endpoints. Subacute exposure to 1-100 μg/L of PS-MPs resulted in adverse physiological effects in C. elegans, and PS-MPs were ingested and accumulated in the intestine of C. elegans. Exposure to 100 μg/L of PS-MPs significantly increased reactive oxygen species (ROS) production, lipofuscin accumulation, and the expression oxidative stress-related genes, which suggests that PS-MPs exposure induced oxidative stress by ROS. In addition, exposure to 100 μg/L of PS-MPs caused a hyperpermeable state of the intestinal barrier and altered the expression of genes related to intestinal development, which indicates intestinal damage in C. elegans. According to Pearson correlation analyses, oxidative stress and intestinal damage were significantly correlated with adverse effects of PS-MPs in C. elegans. Therefore, it was speculated that the toxicity induced by PS-MPs resulted from the combination of oxidative stress and intestinal injury.