The role of ascorbic acid on titanium dioxide-induced genetic damage assessed by the comet assay and cytogenetic tests

Titanium dioxide (TiO₂) is used in several commercial products such as cosmetics, sunscreen, toothpaste and pharmaceuticals. However, some recent investigations have revealed that titanium particles generate potential harmful effects on the environment and humans. Because of its strong antioxidant activity, ascorbic acid (AA) is admitted to act as an anti-mutagenic agent. The present study was undertaken to investigate the protective effect of AA against TiO₂-induced genotoxicity. Sister chromatid exchange (SCE), micronucleus (MN) and the comet assays were used to assess TiO₂-induced genotoxicity and to establish the protective effects of AA. There were significant increases (P<0.05) in both SCE and MN frequencies of cultures treated with TiO₂ as compared to controls. However, co-application of AA (4.87 and 9.73 μM) and TiO₂ resulted in decreases of SCE and MN rates as compared to the group treated with titanium alone. Besides, significant reductions of primary DNA damage (comet assay) were determined when the AA was added to the cell culture medium simultaneously with TiO₂. In conclusion, the preventive role of AA in alleviating TiO₂-induced DNA damage was indicated for the first time in the present study.