Effects of polystyrene nanoparticles on bovine oocyte in vitro maturation

Polystyrene nanoparticles (PS-NPs) have emerged as a significant environmental concern due to their widespread presence and potential toxicity. This study investigates the effects of PS-NPs on bovine oocyte in vitro maturation (IVM) to assess their impact on reproductive health. During IVM, oocytes were exposed to varying concentrations of 100 nm PS-NPs (0, 5, 50, 100, and 200 μg/mL) or of fluorescent 30 nm PS-NPs (0, 5, 35, and 70 μg/mL). Higher PS-NPs concentrations (100 and 200 μg/mL for 100 nm PS-NPs and 70 μg/mL for 30 nm PS-NPs) significantly reduced nuclear maturation rates and increased degeneration. Similarly, cytoplasmic maturation was negatively affected at higher concentrations (P < 0.05). PS-NPs exposure also elevated reactive oxygen species (ROS) levels and reduced glutathione (GSH) content within the oocyte. Notably, PS-NPs were internalized by both oocytes and cumulus cells in a concentration-dependent manner. These findings confirm the reproductive toxicity of PS-NPs, emphasizing their potential to compromise mammalian fertility and raising concerns regarding their environmental and health implications.