柴油废气成分分析及对DNA生物氧化能力

Analysis on diesel oil vehicle exhaust and its oxidative DNA damage

目的 通过研究以柴油为燃料的机动车尾气成分 ,及其对DNA分子的生物氧化能力 ,在分子生物学水平上探讨燃柴油机动车尾气污染物的遗传毒性效应与机制。方法 以DNA加合物 8-羟基脱氧乌苷 (8-OHdG)作为DNA氧化损伤的生物学标志物 ,用高压液相色谱 -电化学 (HPLC -EC)法对染毒后的DNA中 8-OHdG进行定量检测 ,通过气质联用法 (GC -MS)进行有机成分分析和原子吸收法 (AAS)对其进行无机元素分析 ,并从化学组成成分的角度探讨DNA分子生物氧化的分子机理。结果 在颗粒物和挥发性有机物中分别检出有机污染物 10 8种和 9种 ,无机元素 8种和 6种。尾气颗粒物和挥发性有机物均可在体外直接诱导DNA的氧化损伤 ,并呈现一定的剂量 -效应关系。结论 污染物直接的生物氧化作用 ,主要是污染物中存在多种痕量金属离子 ,如Fe2 + 、Cu2 + 等 ,在有氧环境中Fe2 + 可以逐渐被氧化为Fe3 + ,同时O2 变为O· -2 。在Fe2 + 和Fe3 + 存在下 ,超氧阴离子O· -2 通过Fenton反应变为羟自由基·OH ,所产生的羟自由基可直接进攻DNA形成 8-OHdG ,或者进攻污染物中酚类化合物形成多酚或酮类化合物 ,这些化合物具有自氧化作用 ,进而生成大量的超氧自由基和羟自由基 ,构成循环反应。

Objective The genotoxicity and its molecular mechanism of diesel oil vehicle exhaust were discussed through analysing the oxidative DNA damage induced by exhaust components.Methods DNA adduct 8-hydrodeoxyguanosine (8-OHdG) was used as a biomarker of oxidative DNA damage.The level of 8-OHdG in DNA exposed to diesel oil vehicle exhaust was detected by HPLC-EC in vitro.Organic and inorganic components in gasoline vehicle exhaust were analyzed by GC-MS and AAS respectively.The molecular mechanism of oxidative DNA damage was discussed by these components.Results It was found that there were 108 and 9 kinds of organic compounds,8 and 6 kinds of inorganic compounds in particles and volatile organic compounds (VOCs) of diesel oil vehicle exhaust.In addition,particles and VOCs of diesel oil vehicle exhaust could directly induce oxidative DNA damage,and had the dose-response relationship.Conclusion The main reason of the oxidative DNA damage caused by diesel oil vehicle exhaust was that the diesel oil vehicle exhaust containd a lot of polyphenols and quinones compounds and some trace metal ions,which can further produce large amounts of superoxide (O\+\{·-\}\-2) and hydroxyl radicals(·OH),to attack DNA and form 8-OHdG.