PET microplastics alter the transcriptome profile and oxidative stress markers in the liver of immature piglets: an in vivo study

The increasing global contamination with microplastics (MPs) poses a significant threat to human and animal health. Recent studies suggest that exposure to microplastics contributes to various detrimental hepatic effects, including oxidative stress and metabolic dysregulation. The aim of the present study was to investigate the global liver transcriptome, oxidative stress and selected liver function markers in immature piglets (n = 15) exposed to polyethylene terephthalate (PET) MPs for 4 weeks. The animals were divided into three groups: a low-dose MPs exposure group (0.1 g PET MPs/day), a high-dose MPs exposure group (1 g PET MPs/day), and a control group that did not receive MPs. The transcriptome profile of the liver was assessed using RNA-Seq. In addition, markers of oxidative stress (catalase, superoxide dismutase, glutathione peroxidase, glutathione transferase, and malondialdehyde) were determined using specific enzymatic assays, and the levels of selected liver function markers (bilirubin, collagen IV, alanine transaminase and aspartate aminotransferase) were measured by ELISA. The results showed that exposure to MPs, especially at a high dose, significantly altered the hepatic transcriptome profile. A low dose of PET MPs changed the expression of 5 genes, while a high dose affected the expression of 24 genes. The differentially expressed genes were associated with several biological processes such as cholesterol metabolism, transferase activity, and oxidation. Moreover, consumption of MPs resulted in increased catalase activity and decreased activity of superoxide dismutase and glutathione peroxidase in the liver. We also observed an increase in bilirubin and a decrease in collagen type IV, alanine aminotransferase, and aspartate aminotransferase content in the liver. These results suggest that PET MPs ingestion may disrupt systemic homeostasis and contribute to liver dysfunction.