Toxic response of zinc oxide nanoparticles in human epidermal keratinocyte HaCaT cells

Nanoparticles are readily used in cosmetics, concrete and car bumpers; however data on safety of nanoparticles are limited. Abundant resources on environmental toxicology databases are available in many internet websites and these websites contain database on human health and nano-safety. Despite ZnO nanoparticles are widely used, very little data on toxic effects are available. In this study, we examined the toxic effect of ZnO nanoparticles on human epidermal keratinocyte HaCaT cells after exposure at the concentrations of 0, 10, 20, 40 and 80 μg/mL for 24 h. ZnO nanoparticles were assessed by monitoring cytotoxic function of mitochondria by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT assay), membrane leakage of lactate dehydrogenase (LDH assay), reactive oxygen species (ROS) and membrane lipid peroxidation (LPO). Results showed that ZnO nanoparticles reduced the mitochondrial function and induced the leakage of LDH. In addition ZnO nanoparticles induced oxidative stress, where induction of ROS and LPO were observed. Above results demonstrated the significant cytotoxicity in human epidermal keratinocyte HaCaT cells of ZnO nanoparticles, which could be mediated through ROS generation and oxidative stress.