Clothianidin induces DNA damage and oxidative stress in bronchial epithelial cells

Clothianidin (CHN) is a member of the neonicotinoid group of insecticides. Its oxidative and DNA damage potential for human lung cells are not known. Therefore, the present study was designed to examine the effects of CHN on DNA damage and oxidative stress in human bronchial epithelial cells (BEAS-2B) treated with CHN for 24, 72, and 120 hr. Our results indicate that CHN decreased cell viability in a concentration-dependent manner. CHN induced DNA single-strand breaks because alkaline comet parameters such as tail intensity, DNA in the tail, tail moment, and tail length increased. All CHN concentrations also significantly induced the formation of DNA double-strand breaks (DSBs) because it increased phosphorylated H2AX protein foci for all treatment times and p53-binding protein 1 foci for all treatments except for the lowest concentration (0.15 mM) of 120-hr treatment. DNA damage caused by DNA DSBs was not repaired in a 24-hr recovery period. CHN also induced oxidative stress by decreasing reduced glutathione and increasing lipid peroxidation. These results make it necessary to conduct studies about the detailed carcinogenic potential of CHN in humans because it can induce both oxidative and DNA damage.