Co-exposure effects of Titanium Dioxide Nanoparticles and Metals on antioxidant systems and DNA in the fish Hoplias intermedius

Abstract

Metallic nanoparticles are one of the most produced and used engineered nanomaterial and their wide applications lead to environmental contamination. The aquatic environment is the major recipient of wastes containing nanoparticles and other co-occuring contaminants. We aimed to evaluate genotoxic and biochemical effects of acute exposure to nano-TiO2 in the fish Hoplias intermedius and the interaction to metals. Besides assessing the nanoparticles’ physical-chemical properties we performed an acute exposure with 0.1; 1; 10 μg g-1 nano-TiO2, alone and with lead (21 μgg-1) and aluminium (50 μgg-1). A set of biomarkers were evaluated in the liver such as genotoxicity by comet assay and biochemical biomarkers (SOD, CAT, GPx, GSH, EROD, GST). Most of the biomarkers were altered by the metals, and the nanoparticles caused decrease in SOD (0.1 and 1μg g-1), GSH (1μg g-1), and GST (0.1 μg g-1). In co-exposure, some metal effects were attenuated. There was an increase in EROD activity for most co-exposure groups. Nano-TiO2 was not genotoxic in the experimental conditions. We did not observe any increase in DNA breaks in co-exposure, although, nanoparticles changed the response of some biochemical biomarkers.