Vitamin D modulation of brain-gut-virome disorder caused by polystyrene nanoplastics exposure in zebrafish ( Danio rerio )

Background Many studies have investigated how nanoplastics (NPs) exposure mediates nerve and intestinal toxicity through a dysregulated brain-gut axis interaction, but there are few studies aimed at alleviating those effects. To determine whether and how vitamin D can impact that toxicity, fish were supplemented with a vitamin D-low diet and vitamin D-high diet. Results Transmission electron microscopy (TEM) showed that polystyrene nanoplastics (PS-NPs) accumulated in zebrafish brain and intestine, resulting in brain blood–brain barrier basement membrane damage and the vacuolization of intestinal goblet cells and mitochondria. A high concentration of vitamin D reduced the accumulation of PS-NPs in zebrafish brain tissues by 20% and intestinal tissues by 58.8% and 52.2%, respectively, and alleviated the pathological damage induced by PS-NPs. Adequate vitamin D significantly increased the content of serotonin (5-HT) and reduced the anxiety-like behavior of zebrafish caused by PS-NPs exposure. Virus metagenome showed that PS-NPs exposure affected the composition and abundance of zebrafish intestinal viruses. Differentially expressed viruses in the vitamin D-low and vitamin D-high group affected the secretion of brain neurotransmitters in zebrafish. Virus AF191073 was negatively correlated with neurotransmitter 5-HT, whereas KT319643 was positively correlated with malondialdehyde (MDA) content and the expression of cytochrome 1a1 ( cyp1a1 ) and cytochrome 1b1 ( cyp1b1 ) in the intestine. This suggests that AF191073 and KT319643 may be key viruses that mediate the vitamin D reduction in neurotoxicity and immunotoxicity induced by PS-NPs. Conclusion Vitamin D can alleviate neurotoxicity and immunotoxicity induced by PS-NPs exposure by directionally altering the gut virome. These findings highlight the potential of vitamin D to alleviate the brain-gut-virome disorder caused by PS-NPs exposure and suggest potential therapeutic strategies to reduce the risk of NPs toxicity in aquaculture, that is, adding adequate vitamin D to diet. A5myG_s1qHAhSjY9k6V2Q1 Video Abstract