Prebiotic protects against anatase titanium dioxide nanoparticles-induced microbiota-mediated colonic barrier defects

Ingestion of engineered nanoparticles (NPs) can affect gut microbiota composition, and gut bacteria influences colonic epithelial function. The colonic mucus layer is a physical barrier that separates trillions of gut bacteria from the host intestinal epithelial cells. However, the interaction between titanium dioxide (TiO2) NPs, gut microbiota, and intestinal barrier function is less clear. Here we show that short-term ingestion of TiO2 NPs (1 mg/kg/day for 7 days) led to increased Ti burden in male adult murine blood and intestine tissue, as well as colonic epithelial injury, suppressed expression levels of tight junction proteins, and reduced thickness of the luminal mucus layer. Accordingly, male adult mice fed TiO2 NPs had an altered gut microbiota composition, in which the richness of Bifidobacterium was significantly reduced, compared with controls. Mucus layer deterioration can be induced by transplanting microbiota from TiO2 NPs-exposed mice. Prebiotic inulin supplementation prevented TiO2 NPs-induced colonic barrier dysfunction. We hypothesize that the presence of distinct bacteria is crucial for maintaining the mucus layer and prebiotic supplementation can protect against engineered NPs-induced epithelial injury. Our finding may help to better understand the safety of NPs through ingestion.