DNA damage and repair following In vitro exposure to two different forms of titanium dioxide nanoparticles on trout erythrocyte

Abstract

TiO₂ has been widely used to promote organic compounds degradation on waste aqueous solution, however, data on TiO₂ nanotoxicity to aquatic life are still limited. In this in vitro study, we compare the toxicity of two different families of TiO₂ nanoparticles on erythrocytes from Oncorhynchus mykiss trout. The crystal structure of the two TiO₂ nanoparticles was analyzed by XRD and the results indicated that one sample is composed of TiO₂ in the anatase crystal phase, while the other sample contains a mixture of both the anatase and the rutile forms of TiO₂ in a 2:8 ratio. Further characterization of the two families of TiO₂ nanoparticles was determined by SEM high resolution images and BET technique. The toxicity results indicate that both TiO₂ nanoparticles increase the hemolysis rate in a dose dependent way (1.6, 3.2, 4.8 μg mL⁻¹) but they do not influence superoxide anion production due to NADH addition measured by chemiluminescence. Moreover, TiO₂ nanoparticles (4.8 μg mL⁻¹) induce DNA damage and the entity of the damage is independent from the type of TiO₂ nanoparticles used. Modified comet assay (Endo III and Fpg) shows that TiO₂ oxidizes not only purine but also pyrimidine bases. In our experimental conditions, the exposure to TiO₂ nanoparticles does not affect the DNA repair system functionality. The data obtained contribute to better characterize the aqueous environmental risks linked to TiO₂ nanoparticles exposure. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.