Microplastics (MPs) exposure impairs porcine oocyte quality by triggering oxidative stress-directed DNA damage and apoptosis with metabolomic alterations

Microplastics (MPs) are widely present in the environment, and their potential hazards to human health are increasingly a concern. This study aims to investigate the specific impact of MPs on the female reproductive system, particularly on the meiotic maturation of mammalian oocytes. We found that MPs exposure significantly reduced the quality of porcine oocytes, manifested as obstacles in the extrusion of polar bodies, abnormalities in spindle and chromosome structure, and alterations in cortical actin distribution. Through metabolomic analysis, we observed that MPs exposure led to a decrease in the levels of choline and creatine metabolism, both of which play crucial roles in maintaining cell structure and energy metabolism. These changes further impacted mitochondrial function, resulting in mitochondrial dysfunction and an increase in oxidative stress levels within the oocytes. This not only depleted the intracellular antioxidant glutathione but also disrupted the redox balance within the oocytes. The reduction in glutathione (GSH) exacerbated the cell's sensitivity to oxidative damage, leading to DNA damage and apoptosis. These results indicate that MPs disrupt the redox balance of oocytes by interfering with choline and creatine metabolism and by reducing glutathione levels, thereby adversely affecting oocyte maturation. This study not only reveals the mechanisms of reproductive toxicity of MPs on porcine oocyte maturation but also provides new insights into the potential risks of MPs to female reproductive health.