香烟烟气与纳米二氧化钛对人支气管上皮细胞的遗传损伤研究

目的探讨香烟烟气与纳米二氧化钛(nano-TiO2)单独及联合染毒对人支气管上皮细胞株(16-HBE)DNA断裂及染色体畸变的影响。方法将状态良好的16-HBE单独及混合暴露于香烟烟气提取物(cigarette smoke extract,CSE)和nano-TiO2,其终浓度分别为0、0mg/L,50、0mg/L,75、0mg/L,100、0mg/L,0、10mg/L,50、10mg/L,75、10mg/L,100、10mg/L。24h后,采用四甲基偶氮唑盐(MTT)法检测HBE的存活率,以单细胞凝胶电泳检测DNA损伤程度,以微核试验检测染色体畸变。结果除10mg/L nano-TiO2单独染毒组以外,各染毒组的存活率较对照组降低,彗星率(Comet%)较对照组升高,有统计学意义(P0.05);75、100mg/L CSE单独染毒组及各联合染毒组的彗星尾长(Ltail)较对照组升高,有统计学意义(P0.05);100mg/L CSE单独染毒组及100mg/L CSE+10mg/L nano-TiO2联合染毒组的尾部DNA含量(TailDNA%)较对照组升高,有统计学意义(P0.05);100mg/L CSE单独染毒组及75mg/L CSE+10mg/L nano-TiO2,100mg/L CSE+10mg/L nano-TiO2联合染毒组的尾矩(TM)、Olive尾矩(OTM)均较对照组升高,有统计学意义(P0.05);除10mg/L nano-TiO2单独染毒组以外,各染毒组微核率均较对照组升高,有统计学意义(P0.01)。各指标析因分析结果均未显示CSE及nano-TiO2联合染毒有交互作用。CSE与HBE的彗星率和微核率均呈正相关(P0.01)。结论香烟烟气诱导的HBE DNA断裂和染色体畸变随染毒剂量增加而加重;尚未见香烟烟气和nano-TiO2对HBE的遗传损伤具有交互作用。

Genetic Damage of Human Bronchial Epithelial Cells Caused by Cigarette Smoke Combined with Nano-TiO_2

Objective To investigate the genetic damage of human bronchial epithelial cells (HBE) caused by cigarette smoke combined with nano-TiO_2.Methods 16-HBE cells were exposed to cigarette smoke extract (CSE) and nano-TiO_2(mg/L) at the doses of 0 mg/L CSE+0 mg/L nano-TiO_2, 50 mg/L CSE+0 mg/L nano-TiO_2, 75 mg/L CSE+0 mg/L nano-TiO_2, 100 mg/L CSE+0 mg/L nano-TiO_2, 0 mg/L CSE+10 mg/L nano-TiO_2,50 mg/L CSE+10 mg/L nano-TiO_2, 75 mg/L CSE+10 mg/L nano-TiO_2,100 mg/L CSE+10 mg/L nano-TiO_2. After 24 h exposure, HBE viability was evaluated by the methyl thiazolyl tetrazolium (MTT) assay, single cell gel electrophoresis (SCGE, comet assay) was employed to assess DNA damage, chromosomal aberration was measured by micronucleus test. Results Except the group exposed to 10 mg/L nano-TiO_2, HBE viability of the other treatment groups were lower than that of the control group and Comet % of the other treatment groups were higher than that of the control group (P<0.05). Ltail of the groups exposed to 75 mg/L and 100 mg/L CSE and all the combined groups were higher than that of the control group (P<0.05). Tail DNA% of the groups exposed to CSE and nano-TiO_2 at doses of 100 mg/L CSE+0 mg/L nano-TiO_2 and 100 mg/L CSE+10 mg/L nano-TiO_2 were higher than that of the control group (P<0.05). TM and OTM of the groups exposed to CSE and nano-TiO_2 of 100 mg/L CSE+0 mg/L nano-TiO_2, 75 mg/L CSE+10 mg/L nano-TiO_2 and 100 mg/L CSE+10 mg/L nano-TiO_2 were higher compared with the control group (P<0.05). Except the group exposed to 10 mg/L nano-TiO_2, micro-nuclear rates of the other treatment groups were higher than that of the control group (P<0.01). No interaction was seen between cigarette smoke and nano-TiO_2. CSE was positively correlated with Comet% and micro-nuclear rates of HBE in the groups only exposed to NaF or the combined groups (P<0.01). Conclusion Treated with higher dosage of CSE, HBE show more serious DNA breakage and chromosomal aberration with dose-dependent manner, however, there is no interaction between cigarette smoke and nano-TiO_2.