[Values of the micronucleus test on animal epithelial cells exposed to titanium dioxide]

The genetic safety of titanium dioxide (TD)-containing foods and cosmetic products has been little investigated. The study evaluated the mutagenic activity of TD in the micronucleus test with animal visceral mucosal epithelial cells. Two simethicone-coated anatase samples (mean size 160 and 33.2 nm) were inserted into the mouse stomach in doses of 40-200-1000 mg/kg seven times and applied as an ingredient of 10 and 25% cream (doses 250 and 625 mg/kg, respectively) to the hair-sheared rat skin once for 4 hours. Analysis of cytogenetic disorders (micronuclei, protrusions, and the atypical form of the nucleus) revealed no mutagenic properties of TD on the mucosal epithelium of the mouse and rat intestine, mouse prostomach, and rat uterine bladder. Enhanced mitotic activity was observed in all the study tissues after exposure of both samples to TD given in some or in all (in the rat urinary bladder mucosal epithelium) doses.