Genotoxic and oxidative stress potential of nanosized and bulk zinc oxide particles in Drosophila melanogaster

Zinc oxide nanoparticles (ZnONP) are manufactured on a large scale and can be found in a variety of consumer products, such as sunscreens, lotions, paints and food additives. Few studies have been carried out on its genotoxic potential and related mechanisms in whole organisms. In the present study, the in vivo genotoxic activity of ZnONP and its bulk form was assayed using the wing-spot test and comet assay in Drosophila melanogaster. Additionally, a lipid peroxidation analysis using the thiobarbituric acid assay was also performed. Results obtained with the wing-spot test showed a lack of genotoxic activity of both ZnO forms. However, when both particle sizes were tested in the comet assay using larvae haemocytes, a significant increase in DNA damage was observed for ZnONP treatments but only at the higher dose applied. In addition, the lipid peroxidation assay showed significant malondialdehyde (MDA) induction for both ZnO forms, but the induction of MDA for ZnONP was higher for the ZnO bulk, suggestin...