Effects of boric acid and borax on titanium dioxide genotoxicity

Titanium dioxide (TiO2) is a potential carcinogenic/mutagenic agent although it is used in many areas including medical industries and cosmetics. Boron (as boric acid and borax) has also well-described biological effects and therapeutic benefits. In a previous study, sister-chromatid exchanges (SCEs) and micronuclei (MN) rates were assessed in control and TiO2-treated (1, 2, 3, 5, 7.5 and 10 mu M) human whole blood cultures. The results showed that the rates of SCE (at 2, 3, 5, 7.5 and 10 mu M) and MN (at 5, 7.5 and 10 mu M) formation in peripheral lymphocytes were increased significantly by TiO2 compared with the controls. The present study also investigated the genetic effects of boric acid and borax (2.5, 5 and 10 mu M) on cultures with and without TiO2 addition. No significant increase in SCE and MN frequencies were observed at all concentrations of boron compounds. However, TiO2-induced SCE and MN could be reduced significantly by the presence of boric acid and borax. In conclusion, this study indicated for the first time that boric acid and borax led to an increased resistance of DNA to damage induced by TiO2. Copyright (C) 2007 John Wiley & Sons, Ltd.