Effect of Long-Term Intake of Dietary Titanium Dioxide Nanoparticles on Intestine Inflammation in Mice

Early stage exposure of foodborne substances, such as brightening agent titanium dioxide nanoparticles (TiO₂ NPs), can cause long-term effects in adulthood. We aimed to explore the potential adverse effect of long-term dietary intake of TiO₂ NPs. After feeding for 2-3 months from weaning, TiO₂ NPs-exposed mice showed lower body weight and induced intestinal inflammation. However, this phenomenon was not observed in gut microbiota-removed mice. TiO₂ NPs exposure rarely affected the diversity of microbial communities, but significantly decreased the abundance of several probiotic taxa including Bifidobacterium and Lactobacillus. Additionally, TiO₂ NPs aggravated DSS-induced chronic colitis and immune response in vivo, and reduced the population of CD4+T cells, regulatory T cells, and macrophages in mesenteric lymph nodes. Therefore, dietary TiO₂ NPs could interfere with the balance of immune system and dynamic of gut microbiome, which may result in low-grade intestinal inflammation and aggravated immunological response to external stimulus, thus introducing potential health risk.