The widespread use of titanium dioxide nanoparticles (TiO2 NPs) in the food industry has brought about human safety risks related to nanotoxicity. In this study, food-related TiO2 NPs (anatase, 40 nm) were given to rats by oral gavage for 90 days at doses of 10, 100, and 1000 mg/kg bw. An additional two satellite groups underwent the same protocol for 45 days and for 90 days followed by a 28 day recovery. TiO2 NPs tended to agglomerate together in H2O, AGJ, and AIJ. No systemic toxicity was observed after 90 day agglomerated TiO2 NP exposure with no Ti distribution in major tissues/organs. Furthermore, TiO2 NP consumption for 90 days had no impact on microbiota diversity; the community structure of the gut microbiota is shifted to some extent at the genus level. Collectively, the NOAEL of agglomerated TiO2 NPs for 90 days of oral administration was 1000 mg/kg bw, the highest dose tested in male and female rats.
Keywords: TiO2 NPs; agglomerates; distribution; intestinal flora; subchronic oral exposure.