Polyvinyl chloride microplastics induced gut barrier dysfunction, microbiota dysbiosis and metabolism disorder in adult mice

Microplastics (MPs) are a new kind of environmental pollutant that has attracted extensive attention in recent years. MPs can be ingested by multiple organisms and mainly accumulate in the intestine. However, there is still little known about the toxic effects of MPs on humans. Here, we chose the male adult mice as the research model, which were exposed to 2 mu m polyvinyl chloride (PVC) MPs at a concentration of 100 mg/kg for consecutive 60 days, to study the toxicity of PVC-MPs. The changes in gut histology, enzymatic biomarkers, the intestinal microbiome, and metabolomic responses were monitored in mice. The results displayed that the PVC-MPs reduced intestinal mucus secretion and increased intestinal permeability. Moreover, PVC-MPs exposure decreased mRNA expression levels of colonic mucus secretion-related genes, indicating dysfunction of intestinal mucus secretion after exposure to PVC-MPs. With regard to the gut microbiota, high throughput sequencing of the full-length 16S rRNA gene sequencing indicated 15 and 17 kinds of gut microbes changed markedly after PVC-MPs exposure at the genus and species level, respectively. Furthermore, marked alterations in the gut microbiome and fecal metabolic profiles were observed, most of which were related to intestinal injury and barrier dysfunction. These results show that exposure to PVC-MPs leads to intestinal injury and changes gut microbiome composition and metabolome profiles, thus the health risk of PVC-MPs to animals needs more concern. This study helps to provide a new idea about the health risk of PVC-MPs to humans.