Disruption of early embryonic development in mice by polymethylmethacrylate nanoplastics in an oxidative stress mechanism

Polymethylmethacrylate (PMMA) has been used in many products, such as acrylic glass, and is estimated to reach 5.7 million tons of production per year by 2028. Thus, nano-sized PMMA particles in the environment are highly likely due to the weathering process. However, information on the hazards of nanoplastics, including PMMA in mammals, especially reproductive toxicity and action mechanism, is scarce. Herein, we investigated the effect of PMMA nanoplastics on the female reproductive system of mice embryos during pre-implantation. The treated plastic particles in embryos (10, 100, and 1000 μg/mL) were endocytosed into the cytoplasm within 30 min, and the blastocyst development and indices of embryo quality were significantly decreased from at 100 μg/mL. Likewise, the transfer of nanoplastic-treated embryos at 100 μg/mL decreased the morula implantation rate on the oviduct of pseudopregnant mice by 70%, calculated by the pregnant individual, and 31.8% by the number of implanted embryos. The PMMA nanoplastics at 100 μg/mL significantly increased the cellular levels of reactive oxygen species in embryos, which was not related to the intrinsic oxidative potential of nanoplastics. This study highlights that the nanoplastics that enter systemic circulation can affect the early stage of embryos. Thus, suitable action mechanisms can be designed to address nanoplastic occurrence.