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