Exposure to Polystyrene Microplastics Disrupts Blood Cell Homeostasis and Metabolic Profiles in Pregnant Mice and Offspring: The Role of Oxidative Stress and Inflammation.

Micro/nanoplastics (MNPs) are emerging contaminants of concern for maternal and fetal health, yet their effects on the maternal-fetal circulation and serum metabolic homeostasis remain unclear. Here, we investigated the maternal and offspring toxicity of polystyrene microplastics (PS-MPs) and serum metabolomic alterations in dams and offspring. PS-MPs accumulated in multiple tissues, including blood, indicating maternal-to-offspring transfer. Continuous exposure reduced litter size, induced hepatic oxidative stress, and increased IL-6 and TNF-α levels in a dose-dependent manner in both dams and offspring. In dams, PS-MPs also decreased red blood cell and platelet counts and altered leukocyte composition, with increased lymphocyte and decreased neutrophil percentages at the high dose. Untargeted serum metabolomics revealed distinct exposure-related metabolic profiles, including 18 putatively annotated signature metabolites and 26 differentially abundant metabolites. Bilirubin and presqualene diphosphate were exclusively detected in exposed animals, whereas metabolites associated with lipid oxidation and mitochondrial fatty acid β-oxidation were elevated after exposure. RT-qPCR further supported altered expression of genes involved in these pathways. Overall, PS-MPs disrupted hematological homeostasis and metabolic regulation, likely through hepatic lipid peroxidation and systemic inflammation, and serum bilirubin and presqualene diphosphate may serve as candidate biomarkers of exposure.