Cytotoxicity of Nano Zinc Oxide to Human Bronchial Eptithelial Cells

Objective To determine the potential cytotoxicity of ZnO nanoparticles(nano-ZnO) to human bronchial epithelial cell line(16HBE) in vitro.Methods The cell viability of 16HBE exposed to 0-50 μg/ml nano-ZnO for 24,48,and 72 h was evaluated by 3-(4,5-dimethylthiazol)-2,5-diphenltetrazoliumh romide(MTT) assay.Morphological changes,apoptosis and intracellular production of reactive oxygen species(ROS) of 16HBE induced by 0-50 μg/ml nano-ZnO for 24 h exposure were assessed by optical microscope,Hoechst33342/PI dying assay,and using the oxidation-sensitive fluoroprobe in situ loading,respectively.Results Morphological changes were observed in 16HBE exposed to above 25 μg/ml nano-ZnO for 24 h.The cell viability of 16HBE was significantly decreased in a time-and dose-depended manner after 48 h and 72 h exposure to nano-ZnO at concentrations between 5 μg/ml and 50 μg/ml(P0.05).After 24 h exposure to nano-ZnO at concentrations of greater than or equal 5 μg/ml,the intracellular ROS of 16HBE was significantly increased compare to control(P0.05),and it has a highly positive correlation with the concentration of nano-ZnO(r=0.939,P0.05).The rate of apoptosis induced by nano-ZnO(≥25 μg/ml) in 16HBE cells was significantly enhanced compare to control(P0.05).Conclusion Nano-ZnO suspensions showed time-and dose-dependent cytotoxicity reflected in the inhibition of cell viability,oxidative stress and apoptosis of 16HBE cells.