摘要Background Polystyrene nanoplastics(PS-NPs)are becoming increasingly prevalent in the environment with great advancements in plastic products,and their potential health hazard to animals has received much attention.Several studies have reported the toxicity of PS-NPs to various tissues and cells;however,there is a paucity of information about whether PS-NPs exposure can have toxic effects on mammalian oocytes,especially livestock.Herein,porcine oocytes were used as the model to investigate the potential effects of PS-NPs on mammalian oocytes.Results The findings showed that different concentrations of PS-NPs(0,25,50 and 100 μg/mL)entering into porcine oocytes could induce mitochondrial stress,including a significant decrease in mitochondrial membrane potential(MMP),and the destruction of the balance of mitochondrial dynamic and micromorphology.Furthermore,there was a marked increase in reactive oxygen species(ROS),which led to oocyte lipid peroxidation(LPO).PS-NPs expo-sure induced abnormal intracellular iron overload,and subsequently increased the expression of transferrin receptor(TfRC),solute carrier family 7 member 11(SLC7a11),and acyl-CoA synthetase long-chain family member 4(ACSL4),which resulted in ferroptosis in oocytes.PS-NPs also induced oocyte maturation failure,cytoskeletal dysfunction and DNA damage.Cotreatment with 5 μmol/L ferrostatin-1(Fer-1,an inhibitor of ferroptosis)alleviated the cellular toxicity associated with PS-NPs exposure during porcine oocyte maturation.Conclusions In conclusion,PS-NPs caused ferroptosis in porcine oocytes by increasing oxidative stress and altering lipid metabolism,leading to the failure of oocyte maturation.