Evidence that ultrafine titanium dioxide induces micronuclei and apoptosis in Syrian hamster embryo fibroblasts.

Inhaled ultrafine titanium dioxide (UF-TiO2) particles cause pronounced pulmonary inflammation, in contrast to fine TiO2. Previous studies provide evidence for the production of reactive oxygen species by alveolar macrophages, after overloading with UF-TiO2 particles and cytotoxicity of UF-TiO2 in rat lung alveolar macrophages. UF-TiO2 also causes pulmonary fibrosis and lung tumors in rats.