Chronic exposure to polyvinyl chloride microplastics induces liver injury and gut microbiota dysbiosis based on the integration of liver transcriptome profiles and full-length 16S rRNA sequencing data

Abstract

Microplastics (MPs) have become harmful environmental pollutants, and their potential toxicity to organisms has attracted extensive attention. However, the effects of polyvinyl chloride MPs (PVC-MPs) on the liver and their associated mechanism in mice remain obscure. Here, male mice were exposed to 2-μm PVC-MPs (0.5 mg/day) for 60 days and then sacrificed, and their liver, blood and gut feces were subsequently collected for testing. The liver tissue and fecal samples were subjected to RNA sequencing and full-length 16S rRNA sequencing analysis, respectively. Our results showed that the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the mice exposed to PVC-MPs were markedly higher than those in the control group, implying hepatic injury, as evidenced by hepatic histopathological changes. Moreover, the serum and hepatic triglyceride (TG) and total bile acid (TBA) levels were decreased after exposure to PVC-MPs. The RNA sequencing of mouse liver tissue identified a total of 1540 differentially expressed genes (DEGs) associated with 47 pathways, including the lipid metabolic pathway, oxidative stress, and the phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway, and these DEGs were enriched in the mouse livers. The full-length 16S rRNA sequencing analysis of the gut microbiota in mouse fecal samples revealed that PVC-MPs exposure decreased the relative abundance of probiotics and increased the abundance of conditionally pathogenic bacteria. In conclusion, chronic PVC-MPs exposure causes hepatotoxicity and gut microbiota dysbiosis in mice, and these findings provide new insight into the potential risks of PVC-MPs to human health.