Subchronic Oral Toxicity Study of Food-Related Titanium Dioxide Nanoparticles in Rats Involved in Ti Biodistribution and Gut Microbiota.

The widespread use of titanium dioxide nanoparticles (TiO 2 NPs) in the food industry has brought about human safety risks related to nanotoxicity. In this study, food-related TiO 2 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. TiO 2 NPs tended to agglomerate together in H 2 O, AGJ, and AIJ. No systemic toxicity was observed after 90 day agglomerated TiO 2 NP exposure with no Ti distribution in major tissues/organs. Furthermore, TiO 2 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 TiO 2 NPs for 90 days of oral administration was 1000 mg/kg bw, the highest dose tested in male and female rats.