[Effect of 1,4-naphthoquinone aged black carbon on reactive oxygen species and DNA strand breaks in human bronchial epithelial cells].
OBJECTIVE
To study the effect of 1,4-naphthoquinone aged black carbon (BC/1,4-NQ) on reactive oxygen species and DNA strand breaks in human bronchial epithelial cells (16HBE).


METHODS
In the study, 16HBE cells were exposed to BC/1,4-NQ, BC and 1,4-NQ at the concentrations of BC/1,4-NQ (10.0/0.2, 20.0/0.4, 40.0/0.8, 80.0/1.6, 160.0/3.2 mg/L), BC (10.0, 20.0, 40.0, 80.0, 160.0 mg/L), 1,4-NQ (0.2, 0.4, 0.8, 1.6, 3.2 mg/L) for 24, 48, and 72 h, respectively. Cytotoxicity was detected by cell count kit 8 (CCK-8) at the end point. Then the 16HBE cells were exposed to BC/1,4-NQ (20.0/0.4, 40.0/0.8, 80.0/1.6 mg/L), BC (20.0, 40.0, 80.0 mg/L), 1,4-NQ (0.4, 0.8, 1.6 mg/L) for 24 h. The reactive oxygen species (ROS) generation was determined via flow cytometry with DCFH-DA probe. Single cell gel electrophoresis (SCGE) assay was performed to evaluate genotoxicity by Olive tail moment (OTM) value.


RESULTS
Except for the concentration of 10.0/0.2 mg/L within the exposure time 24 h, the cell viabilities of BC/1,4-NQ were significantly lower than the control (P<0.05) within the exposure time 24-72 h, showing a dose-dependent cytotoxicity. Especially, BC/1,4-NQ showed greater cytotoxicity than BC single exposure, lower than 1,4-NQ at the concentration of BC/1,4-NQ≥80.0/1.6 mg/L. BC/1,4-NQ also showed greater ROS generation and OTM value than the control within the exposure time 24 h at each concentration (P<0.05). Especially, the ROS generation and OTM value of BC/1,4-NQ were greater than BC single exposure, lower than 1,4-NQ at the concentration of 80.0/1.6 mg/L (P<0.05).


CONCLUSIONS
BC/1,4-NQ can induce intracellular ROS generation, cytotoxicity and genotoxicity in 16HBE cells. And at high concentration, the intracellular ROS level, cytotoxicity and genotoxicity induced by BC/1,4-NQ were greater than those by BC single exposure, but lower than those by 1,4-NQ.
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Wen-xiao
WX
Zhang
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Jing
J
Shang
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Xin
X
Gao
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Xian-guo
XG
Luan
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Ping
P
Li
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Tian-jing
TJ
Wang
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Gui-ping
GP
Hu
College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Tong
T
Zhu
Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing 100191, China.
Guang
G
Jia
D002460:Cell Line; D002470:Cell Survival; D004249:DNA Damage; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D009285:Naphthoquinones / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D053260:Soot / Q000737:chemistry*
D009285:Naphthoquinones; D017382:Reactive Oxygen Species; D053260:Soot; C035342:1,4-naphthoquinone