Evaluation of cytogenotoxicity and oxidative stress parameters in male Swiss mice co-exposed to titanium dioxide and zinc oxide nanoparticles.

A number of studies have investigated the adverse toxic effects of titanium dioxide (TiO2) nanoparticles (NPs) or zinc oxide (ZnO) NPs. Information on the potential genotoxic effects of the interactions of TiO2 NPs and ZnO NPs in vivo is lacking. Therefore, this study was designed to investigate the cytogenotoxicity of TiO2 NPs or ZnO NPs alone or their mixtures using the bone marrow micronucleus assay, and mechanism of damage through the evaluation of oxidative stress parameters in the liver and kidney tissues of Swiss mice. Intraperitoneal administration of doses between 9.38 and 150.00 mg/kg of TiO2 NPs or ZnO NPs or TiO2 NPs + ZnO NPs was performed for 5 and 10 days, respectively. TiO2 NPs alone induced a significant (P <  0.05) increase in micronucleated (Mn) polychromatic erythrocytes (PCEs) at the applied doses compared with the negative controls, with a significant difference between 5 and 10 days for TiO2 NPs alone and TiO2 NPs + ZnO NPs. Concurrently, TiO2 NPs alone for 5 days and TiO2 NPs and TiO2 NPs + ZnO NPs for 10 days significantly (P <  0.05) decreased the percentage PCE: normochromatic erythrocyte (NCE) indicating cytotoxicity; with a significant difference between the two periods. Significant (P <  0.001) changes in the activities of superoxide dismutase (SOD) and catalase (CAT), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were observed in the liver and kidney of mice exposed to TiO2 NPs or ZnO NPs alone or their mixtures. These results suggest that TiO2 NPs alone was genotoxic; TiO2 NPs and TiO2 NPs + ZnO NPs were noticeably cytotoxic while ZnO NPs was not cytogenotoxic. The individual NPs or their mixtures induced oxidative stress.