Effect of Zinc Oxide nanoparticles on cellular oxidative stress and antioxidant defense mechanisms in mouse liver

Abstract

Zinc oxide nanoparticles (ZnO₂), a common ingredient of cosmetics has a huge variety of applications. Previous studies reported oxidative stress mediated toxicity of ZnO₂ nanoparticles on various mammalian cell lines. Although zinc (Zn) is an essential mineral at higher concentrations this metal is toxic. The present study focused on size determination by monitoring changes in activities of antioxidant defense mechanism in response to oxidative stress induced by ZnO₂ nanoparticles using mouse liver tissue homogenates. The study also investigated effects of oxidative stress induced DNA damage by determining formation of 8-OHdG in mouse liver homogenate. A cytotoxicity assay was also carried out in L929 cells to determine cell viability. The results of the study indicated that 50μg/ml of ZnO₂ nanoparticles induced 50% cell death. Alterations in antioxidant parameters and 8-OHdG were also noted. Data showed that there was a concentration-dependent fall in cell viability, decrease antioxidant enzyme levels and increase formation of DNA adduct (8-OHdG) when mouse liver tissue homogenate were exposed to ZnO₂ nanoparticles.

Keywords:

• oxidative stress
• cytotoxicity
• anti oxidant
• 8-OHdG

Acknowledgements

Authors are thankful to Prof. K. Radhakrishan, Director and Head, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology for providing the facilities to carry out the work. We also acknowledge the technical assistance of Ms. Leji B, Mr. Shaji S, Mr. Harikumar G.