Acute exposure to titanium dioxide (TiO₂) induces oxidative stress in zebrafish gill tissues

Abstract

Titanium dioxide (TiO₂) produced globally is estimated to reach 6.8 million tonnes in 2016. The extensive use of TiO₂ will thus result in environmental exposure to these nanoparticles (NPs). At present, there is limited information on the ecotoxicolgical consequences of TiO₂ NP exposure focusing on aquatic life. Hence, the aim of this study was to examine toxicity of TiO₂NPs to address the risks using a zebrafish model system. In both qualitative and quantitative analyses, TiO₂ NP was found to accumulate in gills of treated groups. Decreased activity of acetylcholine esterase as well as activities of both enzymatic and nonenzymatic antioxidants was observed. In contrast, there was an increase in levels of protein content, reactive oxygen species, protein carbonyls, and lipid peroxidation products. Fourier transform infrared spectroscopy (FT-IR) spectra reveal a stress response of gill tissue in TiO₂-treated fish. Distortion in the normal architecture of the gill was found upon histological examination. Our results demonstrate that TiO₂ NP induced oxidative stress leading to respiratory distress in zebrafish.

Keywords:

• acute toxicity
• ecotoxicity
• gill tissues
• nanotitania
• oxidative stress
• zebrafish