目的：研究1,4-萘醌老化黑碳（1,4-naphthoquinone aged black carbon, BC/1,4-NQ）对人支气管上皮细胞（16HBE）活性氧水平和DNA链断裂的影响。方法：分别用BC/1,4-NQ及相对应质量浓度的BC和1,4-NQ（BC/1,4-NQ的质量浓度分别为：10.0/0.2、20.0/0.4、40.0/0.8、80.0/1.6、160.0/3.2 mg/L，BC的质量浓度分别为：10.0、20.0、40.0、80.0、160.0 mg/L，1,4-NQ的质量浓度分别为：0.2、0.4、0.8、1.6、3.2 mg/L）染毒16HBE细胞24、48、72 h，通过cell counting kit-8 (CCK-8)法检测细胞毒性。再以不同剂量的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）染毒16HBE细胞24 h，采用2′,7′二氯荧光黄双乙酸盐探针（DCFH-DA）检测细胞内活性氧（reactive oxygen species, ROS）水平，通过单细胞凝胶电泳实验，以Olive尾距为指标，评价DNA链断裂遗传毒性。结果：除10.0/0.2 mg/L剂量染毒24 h后BC/1,4-NQ未见明显的细胞毒性，在各染毒时间点、各剂量BC/1,4-NQ的细胞存活率均显著低于对照组（P<0.05），并表现出一定的剂量依赖效应。当BC/1,4NQ≥80.0/1.6 mg/L时，BC/1,4-NQ的细胞存活率要低于BC单独处理组、高于1,4-NQ处理组（P<0.05）。此外，各剂量BC/1,4-NQ均可引起16HBE胞内ROS含量及Olive尾距增加，并显著大于对照组（P<0.05），表现出一定的剂量依赖效应；当BC/1,4-NQ为80.0/1.6 mg/L时，BC/1,4-NQ的胞内ROS含量和Olive尾距显著大于BC单独处理组、小于1,4-NQ处理组（P<0.05）。结论：以BC/1,4-NQ处理16HBE细胞，可诱导细胞内ROS水平升高，并产生细胞毒性和遗传毒性，且在较高剂量下，BC/1,4-NQ的细胞毒性、胞内ROS水平和遗传毒性要高于BC单独处理组，低于1,4-NQ单独处理组。

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). Conclusion: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.