Efeitos de microplásticos de poliestireno no balanço redox da placenta humana

Abstract

Microplastics (MP) are environmental pollutants with the potential to harm living organisms. MPs have been shown to accumulate in human organs, including the placenta. Here, we investigated the biochemical impact of 5 μm polystyrene microplastics (PS-MP) on term placental chorionic villi explants, focusing on cytotoxicity, oxidative stress, metabolic changes, and the potential of MP to cross the placental barrier. Placental explants were exposed to 100 μg/mL of PS-MP for 72 hours. A significant increase in cytotoxicity over time (p < 0.01) could be observed by lactate dehydrogenase (LDH) release assay. Mitochondrial and overall superoxide anion (p < 0.01 and p < 0.05, respectively) and hydrogen peroxide (p < 0.001) were substantially increased. PS-MP exposure led to a reduction in total sulfhydryl (SH) content (p < 0.05) and the activities of antioxidant enzymes superoxide dismutase (SOD, p < 0.01) and catalase (CAT, p < 0.05), whereas glutathione peroxidase (GPx) activity increased (p < 0.05) and the oxidized/reduced glutathione ratio was diminished (p < 0.05). Markers of oxidative damage, such as malondialdehyde and carbonylated proteins, also increased significantly (p < 0.001 and p < 0.01, respectively), indicating altogether oxidative stress. In conclusion, the study demonstrates that a high concentration of PS-MP induces time-dependent cytotoxicity and oxidative stress. As such, it is paramount to expand our research efforts to elucidate the comprehensive effects of MP contamination on pregnancy, and the repercussions on the subsequent generations.