TiO 2 -NPs and cadmium co-exposure: in vitro assessment of genetic and genomic DNA damage on Dicentrarchus labrax embryonic cells

The increased titanium dioxide nanoparticles ( ­ TiO 2 -NPs) spread and their interaction with organic and inorganic pollutants arouses concern for the potential hazards for organisms and environment. This study tested in vitro the genotoxic effects of ­TiO 2 -NPs (1 ?g/mL) and cadmium (Cd) (0.1 ?g/mL) co-exposure using Dicentrarchus labrax embryonic cells (DLEC)as experimental model. The genotoxicity tests (Comet assay, Diffusion Assay and Random Amplification of Polymorphic DNA (RAPD-PCR) were conducted after 3, 24 and 48 hours of exposure to TiO 2 -NPs and Cd alone and in combination. The results showed that the percentage of DNA damage and apoptotic cells increases following 48 hours TiO 2 -NPs exposure, while DNA instability was detected for all the times tested. Cd induced genotoxic effects starting from 3 hour-exposure and for all the treatment times. Cd + TiO 2 -NPs co-exposure did not cause any genomic damage or apoptosis for all the exposure times. The possibility that Cd and TiO 2 -NPs form aggregates no longer able of enetrating the nucleus and damaging the genetic material is discussed.