Physiological and histopathological alterations in male Swiss mice after exposure to titanium dioxide (anatase) and zinc oxide nanoparticles and their binary mixture

Abstract

Existing studies have shown the systemic damage of titanium dioxide (TiO₂) or zinc oxide (ZnO) nanoparticles (NPs), but there is little or no existing knowledge on the potential adverse toxic effects of the mixture of the two. In order to investigate the in vivo toxic effect of the mixture of TiO₂ NPs and ZnO NPs, the acute toxicities of TiO₂ NPs, ZnO NPs by themselves, and their mixture (1:1) were determined. The systemic toxicities of the individual NPs and mixture were evaluated in mice using hematological indices, hepatic, renal, and lipid profile parameters, and histopathology as endpoints. NPs were intraperitoneally administered at doses of 9.38, 18.75, 37.50, 75.00, and 150.00 mg/kg bw each. Individual NPs and their mixture were administered daily for 5 and 10 d, respectively. The LD₅₀ of ZnO NPs was 299.9 mg/kg while TiO₂ NPs by themselves or TiO₂ NPs + ZnO NPs were indeterminate due to the absence of mortality of the male mice treated. TiO₂ NPs, ZnO NPs by themselves and TiO₂ NPs + ZnO NPs induced significant alterations in the hematological and biochemical parameters, with higher toxicity at 10 d. Histopathological lesions were observed in the liver, kidneys, spleen, heart, and brain of mice treated with the individual NPs and their mixture. TiO₂ NPs + ZnO NPs were able to induce a higher systemic toxicity than TiO₂ NPs or ZnO NPs individually. Our data suggest that more comprehensive risk assessments should be carried out on the mixture of NPs before utilization in consumer products.

Keywords:

• Nanotoxicology
• systemic toxicity
• mixture
• titanium dioxide nanoparticles
• zinc oxide nanoparticles

Acknowledgments

This manuscript is a part of Opeoluwa Ogunsuyi’s (nee Fadoju) PhD thesis. The authors wish to thank Prof. O. O. Sonibare of the Department of Chemistry, University of Ibadan, Nigeria for providing the ultrasonicator. We acknowledge the technical assistance of Samuel Odebamowo and Naomi Adeyemo. The authors would like to thank Lindsey Auguin (LIST, Luxembourg) for the language corrections. The teamwork between our institutions in Nigeria and Luxembourg was originated courtesy of the ‘Meet the expert’ initiative during SOT2017 in Baltimore, USA.

Disclosure statement

The authors declare that there is no conflict of interest.

Additional information

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.