Nanoplastics Induce More Serious Microbiota Dysbiosis and Inflammation in the Gut of Adult Zebrafish than Microplastics.

Abstract

Microplastics (MPs) (< 5mm) and nanoplastics (NPs) (< 100nm) are emerging environmental pollutants and have been proved could cause a series of toxicity in aquatic organisms. In this study, the effects on gut microbiota of adult zebrafish exposed for 21days to 10μg/L and 1mg/L of MPs (8μm) and NPs (80nm) were evaluated. We analyzed the intestinal microbial community of zebrafish using high throughput sequencing of the 16S rRNA gene V3-V4 region and also performed transcriptional profiling of the inflammation pathway related genes in the intestinal tissues. Our results showed that both spherical polystyrene MPs and NPs could induce microbiota dysbiosis in the gut of zebrafish. The flora diversity of gut microbiota significantly increased under a high concentration of NPs. At the phylum level, the abundance of Proteobacteria increased significantly and the abundance of Fusobacteria, Firmicutes and Verrucomicrobiota decreased significantly in the gut after 21-day exposure to 1mg/L of both MPs and NPs. Furthermore, interestingly, the abundance of Actinobacteria decreased in the MPs treatment groups but increased in the NPs treatment groups. At the genus level, revealed that the relative abundance of Aeromonas significantly increased both in the MPs and NPs treatment groups. Moreover, it was observed that NPs increased mRNA levels of il8, il10, il1β and tnfα in the gut, but not in MPs exposure group, indicating that the NPs may have a more serious effect on the gut of zebrafish than MPs to induce microbiota dysbiosis and inflammation in the gut.