Polystyrene microplastics exacerbated liver injury from cyclophosphamide in mice: Insight into gut microbiota

Microplastics (MPs) have infiltrated human food system globally, and the latent health risks have been well-described. However, the impact of pre-consumed MPs on liver resistance to foreign robust stimuli remains unclear. In this study, we developed a mouse model drinking roughly 18 and 180 mu g/kg/day polystyrene MPs for 90 days, then intraperito-neally injected mice with 80 mg/kg cyclophosphamide (CTX) to investigate whether chronic pre-exposure to MPs ag-gravates hepatoxicity induced by CTX. Slight liver injury was found in single CTX-treated mice, while more significant liver histopathological damage, inflammation and oxidative stress elicited by CTX were observed in pre-drinking MPs mice. Moreover, chronic exposure of MPs induced remarkable colonic impairments (e.g., leaky gut, mild inflammation and repressed antioxidant activity) as well as gut microbiota perturbation, which manifested positive association with aggravated hepatotoxicity via spearman correlation analysis. Fecal microbiota transplantation (FMT) trail was con-ducted to ulteriorly demonstrate the critical role of MPs-altered gut bacteria in exaggerated liver susceptibility to CTX stimulation. In conclusion, our study provided an insight that the adverse impact of MPs could be best revealed when animals suffering attack from hazardous substance. It also contributes to comprehensive assessment of health risk from environmentally pervasive MPs.

Automated summary

This study reveals that chronic pre-exposure to microplastics may aggravate cyclophosphamide-induced liver injury. Long-term exposure to microplastics also leads to colonic impairments and gut microbiota perturbation, which contribute to increased liver susceptibility to hazardous substances.