Effects of exposure to polyethylene microplastics on embryotoxicity, teratogenesis, and oxidative stress in Xenopus laevis embryos and larvae

Polyethylene is a key component of the global plastic polymer demand, accounting for approximately 30% and generating an annual volume of approximately 140 million tons. The presence of these microplastics in aquatic ecosystems, including wastewater, rivers, seas, estuaries, groundwater, and drinking water, poses a significant risk to aquatic organisms. The current study evaluated the effect of polyethylene-microplastics on embryonic development and oxidative stress in Xenopus laevis embryos and larvae. In accordance with the guidelines set forth in the standard protocol for conducting the frog-Xenopus embryo teratogenesis assay, embryos were subjected to various environmentally relevant concentrations of PE-MP (3.1, 6.2, 12.5, 25, 50, and 100 mg L-1) for a period of 96 h. This study evaluated mortality, presence and severity of malformations, growth (larval size), and biomarkers of oxidative stress, including lipid peroxidation, hydroperoxide content, protein carbonyl content, and SOD and CAT enzyme activities. The results demonstrated a concentration-dependent increase in mortality, frequency and severity of malformations, and alterations in oxidative stress biomarkers in X. laevis embryos and larvae exposed to PE-MP. Specifically, exposure to PE-MP led to a significant decrease in larval size and a significant increase in oxidative stress biomarkers, indicating embryotoxic and teratogenic effects. These findings emphasize the need for future research to explore the effects of MPs on embryonic development in other aquatic organisms.