DNA Damage and Repair Following In Vitro Exposure to Two Different Forms of Titanium Dioxide Nanoparticles on Trout Erythrocyte

摘要

TiO_2 has been widely used to promote organic compounds degradation on waste aqueous solution, however, data on TiO_2 nanotoxicity to aquatic life are still limited. In this in vitro study, we compare the toxicity of two different families of TiO_2 nanoparticles on erythrocytes from Oncorhynchus mykiss trout. The crystal structure of the two TiO_2 nanoparticles was analyzed by XRD and the results indicated that one sample is composed of TiO_2 in the anatase crystal phase, while the other sample contains a mixture of both the anatase and the rutile forms of TiO_2 in a 2:8 ratio. Further characterization of the two families of TiO_2 nanoparticles was determined by SEM high resolution images and BET technique. The toxicity results indicate that both TiO_2 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, TiO_2 nanoparticles (4.8 μg mL~(-1)) induce DNA damage and the entity of the damage is independent from the type of TiO_2 nanoparticles used. Modified comet assay (Endo III and Fpg) shows that TiO_2 oxidizes not only purine but also pyrimidine bases. In our experimental conditions, the exposure to TiO_2 nanoparticles does not affect the DNA repair system functionality. The data obtained contribute to better characterize the aqueous environmental risks linked to TiO_2 nanoparticles exposure.