Gábelová Alena, Valovicová Zuzana, Horváthová Eva, Slamenová Darina, Binková Blanka, Srám Radim J, Farmer Peter B
Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava, Slovak Republic.
Mutat Res. 2004 Sep 12;563(1):49-59. doi: 10.1016/j.mrgentox.2004.05.014.
The genotoxic potential of extractable organic matter (EOM) associated with the respirable particulate matter (PM <10 microm) of atmospheric pollution has been determined in three European cities--Prague (Czech Republic, two monitoring sites, Libus and Smíchov), Kosice (Slovak Republic) and Sofia (Bulgaria) using the alkaline single-cell gel electrophoresis (the comet assay). The EOM samples were extracted by dichloromethane from ambient airborne particles collected daily (24 h intervals) during 3-month sampling periods in winter and summer seasons. The human metabolically competent cell line Hep G2 was used as a test system and benzo[a]pyrene (BaP), a known carcinogen, was applied as a positive control (internal standard) in each electrophoretic run. Two-hour exposure of Hep G2 cells to equivalent EOM concentrations ranging from 5 to 150 microg EOM/ml resulted in a linear dose-dependent increase of DNA migration (r > 0.9, P < 0.01). A less significant dose-response (r = 0.61) was only induced by the EOM sample from the locality Prague-Libus (PRG-LB) in the winter. Generally, a 1.5 to four-fold increase of DNA strand breaks over the background control level was determined in EOM-exposed cells. In order to compare the genotoxic potential of individual EOMs, a mathematical model was used to correct the 'real' data. No substantial location- or season-related differences were found in EOM genotoxicity (EOM microg/ml), except for the EOM sample from Sofia, collected in the summer. This EOM sample induced a nearly two-fold lower level of DNA damage in comparison with other EOMs. On the other hand, clear statistically significant location- and season-related differences (P < 0.001) in ambient air genotoxicity were determined when the EOM quantity per cubic meter of air (microg/m3) was taken into account. In that case, the genotoxicity of winter air pollution was six- to 10-fold higher in comparison with summer air. The air pollution genotoxicity in individual localities rose during the winter season in the order: PRG-LB < Kosice < Prague-Smíchov (PRG-SM) < Sofia, while during the summer season the highest ambient air genotoxicity was revealed in the locality Prague-Smíchov and approximately equal air pollution genotoxicity was determined among localities Prague-Libus, Kosice and Sofia (PRG-LB approximately Kosice approximately Sofia < PRG-SM). The greatest overall air pollution genotoxicity was determined in the locality Sofia during the winter season. In a time course study to evaluate the kinetics of DNA strand break rejoining it was shown that the level of DNA strand breaks in EOM-exposed cells has returned to near the background level within 24 h after the treatment.
利用碱性单细胞凝胶电泳（彗星试验），在欧洲三个城市——布拉格（捷克共和国，两个监测点，利布斯和斯米乔夫）、科希策（斯洛伐克共和国）和索非亚（保加利亚），测定了与大气污染中可吸入颗粒物（PM<10微米）相关的可提取有机物（EOM）的遗传毒性潜力。在冬季和夏季的3个月采样期内，每天（间隔24小时）从环境空气中收集颗粒物，用二氯甲烷提取EOM样品。将具有人类代谢活性的细胞系Hep G2用作测试系统，并将已知致癌物苯并[a]芘（BaP）作为每次电泳运行的阳性对照（内标）。将Hep G2细胞暴露于浓度范围为5至150微克EOM/毫升的等效EOM中2小时，导致DNA迁移呈线性剂量依赖性增加（r>0.9，P<0.01）。仅在冬季，来自布拉格-利布斯地区（PRG-LB）的EOM样品诱导出不太显著的剂量反应（r = 0.61）。一般来说，在暴露于EOM的细胞中，DNA链断裂比背景对照水平增加了1.5至4倍。为了比较各个EOM的遗传毒性潜力，使用数学模型对“真实”数据进行校正。除了夏季在索非亚采集的EOM样品外，未发现EOM遗传毒性（EOM微克/毫升）与地点或季节相关的实质性差异。与其他EOM相比，该EOM样品诱导的DNA损伤水平低近两倍。另一方面，当考虑每立方米空气中EOM的量（微克/立方米）时，确定了环境空气遗传毒性与地点和季节相关的明显统计学差异（P<0.001）。在这种情况下，冬季空气污染的遗传毒性比夏季空气高6至10倍。各个地点的空气污染遗传毒性在冬季按以下顺序上升：PRG-LB<科希策<布拉格-斯米乔夫（PRG-SM）<索非亚，而在夏季，布拉格-斯米乔夫地区的环境空气遗传毒性最高，在布拉格-利布斯、科希策和索非亚地区（PRG-LB≈科希策≈索非亚<PRG-SM）确定了大致相等的空气污染遗传毒性。在冬季，索非亚地区的总体空气污染遗传毒性最大。在一项评估DNA链断裂重新连接动力学的时间进程研究中表明，暴露于EOM的细胞中的DNA链断裂水平在处理后24小时内已恢复到接近背景水平。
