Ozonized carbon black induces mitochondrial dysfunction and DNA damage.
Black carbon and tropospheric ozone (O3), which are major air pollutants in China, are hazardous to humans following inhalation. Black carbon can be oxidized by O3forming secondary particles of which the health effects are unknown. The present study utilized carbon black as a representative of black carbon to characterize the cytotoxicity induced by secondary particles in bronchial epithelial cells (16HBE) and C57BL/6J mice, and to investigate the implicated molecular pathways. Two types of carbon black including untreated carbon black (UCB) and ozonized carbon black (OCB) were presented. The effects of carbon black on cell viability, intracellular reactive oxygen species (ROS), oxidized/reduced glutathione ratio, mitochondrial membrane potential (MMP), intracellular ATP, and mitochondrial cytochrome c to cytoplasmic cytochrome c ratio were assessed in 16HBE. In addition, an alkaline comet assay and a cytokinesis-block micronucleus (CBMN) test with 16HBE cells in vitro and ELISA method for serum 8-hydroxy-2'-deoxyguanosine (8-OHdG) and a bone marrow micronucleus (BMN) test with C57BL/6J mice in vivo were performed to detect the genotoxicity. When compared with UCB exposed cells, OCB exposed cells had decreased cell viability, increased cell death rate, increased comet length and decreased MMP at 24 h exposure. UCB induced higher level of intracellular ROS than OCB from 4 to 23 h. No changes were observed for both OCB and UCB in serum 8-OHdG, intracellular ATP and mitochondrial cytochrome c to cytoplasmic cytochrome c ratio. The results of CBMN and BMN tests are negative. Intracellular ROS induced by OCB was lower than that of UCB. In summary, ozonization enhances the mitochondrial toxicity and genotoxicity of carbon black. Oxidative stress may not dominate in toxic effects of OCB. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 944-955, 2017.
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Xin
X
Gao
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Huadong
H
Xu
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, P.R. China.
Jing
J
Shang
Medical and Healthy Analytical Center, Peking University, Beijing, 100191, P.R. China.
Lan
L
Yuan
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Yongming
Y
Zhang
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Lele
L
Wang
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Wenxiao
W
Zhang
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Xianguo
X
Luan
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Guiping
G
Hu
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Hongqian
H
Chu
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, P.R. China.
Tong
T
Zhu
Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, 100191, P.R. China.
Guang
G
Jia
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000393:Air Pollutants / Q000633:toxicity; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000187:drug effects; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010126:Ozone / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D053260:Soot / Q000633:toxicity*
D000393:Air Pollutants; D017382:Reactive Oxygen Species; D053260:Soot; D010126:Ozone; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D005978:Glutathione
black carbon; carbon black; mitochondria; oxidative stress; ozone