Exposure to polystyrene nanoplastics induces lysosomal enlargement and lipid droplet accumulation in KGN human ovarian granulosa cells

Given the ubiquitous presence of plastic products in daily life, human exposure to nanoplastics (NPs) is inevitable. Previous studies have suggested that exposure to polystyrene nanoplastics (PSNPs) may contribute to reproductive disorders; however, the underlying mechanism remains elusive. The goal of this study was to investigate the impact of PSNPs on KGN human ovarian granulosa cells. KGN cells were exposed to varying concentrations of PSNPs (0-400 μg/mL) for 48 h; alterations in cell survival and morphology were assessed to elucidate potential toxic effects. PSNPs were shown to enter KGN cells. Exposure to PSNPs did not induce significant changes in cytotoxicity, Calcein intensity, or active mitochondria levels in KGN cells. However, PSNP exposure did induce a dose-dependent increase in cytoplasmic vacuoles and an increase in total lysosome area and in the numbers of lipid droplets in KGN cells. Our findings provide compelling evidence that PSNPs can penetrate cell cytoplasm and induce toxicity, resulting in an elevation in the numbers of lysosomes and lipid droplets. This may represent one mechanism by which PSNPs exert damage on the reproductive system.