香烟烟雾成分分析及其对DNA生物氧化能力研究

目的 从分子生物学水平上探讨香烟烟雾对DNA的生物氧化能力。方法 以DNA加合物8－羟基脱氧鸟苷（8－OHdG）作为DNA氧化损伤的生物学标志物,用高压液相色谱－电化学检测法对香烟烟雾染毒后的DNA中8－OHdG进行定量。通过气质联用法（GC－MS）对香烟烟雾进行有机分成分析,用原子吸收法（AAS）对其进行无机元素分析。结果 香烟烟雾颗粒物和挥发性有机物可不同程度地引起DNA基损伤产生8－OHdG,并分别检出有机污染物157种和78种,无机元素5种。香烟烟雾对DNA的生物氧化能力主要是由于存在大量有机污染物,其中的醌类、多酚等化合物具有自氧化作用,在体外可产生大量的活性氧自由基,并在金属的催化作用下进攻DNA的碱基,形成加合物8－OHdG。结论 香烟烟雾对DNA具有氧化能力,香烟烟雾具有直接的遗传毒性效应。     

燃汽油机动车尾气致核酸分子氧化损伤效应研究

目的：通过研究燃汽油机动车尾气成分，及其对DNA分子的氧化损伤，在分子生物学水平上探讨燃汽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-羟基脱氧鸟苷(8-OHdG)作为DNA氧化损伤的生物学标志物，用高压液相色谱-电化学检测(HPLC-EC)法对污染物染毒后的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氧化损伤的分子机理。结果：在燃汽油机动车尾气的颗粒物和挥发性有机物中分别检出有机污染物85种和46种，无机元素7种和5种。燃汽油机动车尾气颗粒物和挥发性有机物均可在体外直接诱导DNA氧化损伤，尾气颗粒物还可诱导大鼠肺组织DNA氧化损伤，并呈现一定的剂量—反应关系。结论：污染物直接以及间接的氧化作用，源于含有醌类、多酚等具有自氧化作用的化合物，不需要任何生物活化系统，在体外就可产生大量的活性氧自由基，并在金属离子的催化作用下进攻DNA的碱基形成8-OHdG，产生遗传毒性效应，而8-OHdG是DNA氧化损伤的较好的效应标志物。     

烹调油烟雾诱导核酸氧化损伤及其标志物8-羟基脱氧鸟苷的形成机制

目的 了解烹调油烟雾的遗传毒性效应。方法 以核酸加合物8-羟基脱氧鸟苷(8-OHdG)作为DNA氧化损伤的生物学标志物,用高效液相色谱-电化学检测法(HPLC-EC)对烹调油烟雾染毒的小牛胸腺DNA及Wistar大鼠气管灌注染毒的肺组织DNA中8-OHdG进行定量检测,通过气质联用法(GC-MS)进行有机成分和原子吸收法(AAS)进行无机元素分析,并从混合污染物化学组成成分的角度推断了烹调油烟雾造成DNA氧化损伤的分子机理。结果体外试验表明烹调油烟雾的各组分,包括油烟冷凝物、残留油、油烟颗粒物、油烟挥发性有机物均能能诱导DNA氧化产生8-OHdG,产生量的顺序为残留油>冷凝物>油烟颗粒物>油烟挥发性有机物。体内实验结果表明油烟冷凝物可诱导大鼠肺组织DNA的氧化且具有剂量一反应关系和时间一效应关系。结论烹调油烟雾具有明确的遗传毒性,可诱导核酸氧化产生加合物8-OHdG,其机制可能是烹调油混合污染物中存在痕量金属离子如Fe2+、Cu2+等,介导Fenton反应生成羟自由基,直接进攻DNA造成氧化损伤。     

丙烯醛对DNA分子的损伤作用

目的 通过研究丙烯醛对DNA分子的损伤,探讨丙烯醛的遗传毒性效应及其分子机制。方法 应用单细胞凝胶电泳技术检测丙烯醛引起的DNA断裂、DNA交联以及DNA．蛋白质交联;应用液相色谱．电化学法研究丙烯醛致DNA分子产生氧化损伤标志物8-羟基脱氧鸟苷(8-OHdG)。结果 丙烯醛可诱导人外周血淋巴细胞DNA发生链断裂,但不引起DNA-DNA、DNA-蛋白质交联;丙烯醛与小牛胸腺DNA的体外作用较弱,但在铁离子介导下对DNA的氧化能力增强。可产生一定量的8-OHdG加合物;动物实验表明丙烯醛诱导大鼠肺组织DNA氧化损伤生成少量8-OHdG。结论 丙烯醛具有直接的遗传毒性效应,产生自由基造成DNA氧化损伤是其遗传毒性效应的主要途径。     

室内生源性多环芳烃对DNA的氧化损伤

目的 了解室内生活污染来源-吸烟和烹调产生的多环芳烃(PAHs)种类与含量，及其对DNA的氧化损伤作用。方法 采集室内烹调油烟和环境烟草烟雾颗粒物，应用气相色谱-质谱-选择性离子监测技术(GC-MS-SIM)定量检测10种PAHs，并用10种混合PAHs经气管灌注染毒大鼠，用液相色谱结合电化学检测技术测定肺组织DNA中产生的氧化损伤标志物8-羟基脱氧鸟苷(8-OHdG)。结果 PAHs广泛存在于烹调油烟冷凝物、油烟颗粒物以及环境烟草烟雾的主、侧流烟雾颗粒物之中。其标准混合物可诱导大鼠肺组织DNA氧化损伤形成8-OHdG，并呈现明确的剂量一反应关系。结论 PAHs的遗传毒性效应和潜在的致癌效应存在着一条氧化代谢产生羟基自由基进攻核酸的途径。     

柴油废气成分分析及对DNA生物氧化能力

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。     

8-羟基脱氧鸟苷在污染物遗传毒性研究中的应用分析

遗传毒性是环境毒理学研究的一项重要内容。遗传毒性可以由多种环境因素,经过多种生物学机制引起。外源性氧化性环境污染物进入体内所致的生物大分子的氧化损伤,是遗传毒性最为常见的生物学机制之一。主要表现为生物大分子（如DNA、蛋白质、脂类等）氧化损伤,以及随之发生的结构和功能改变,并最终导致基因突变、细胞癌变及生成肿瘤等现象。8-羟基脱氧鸟苷（8-hydroxy-2-deoxyguanosine,8-OHdG）是活性氧自由基（如羟自由基、单线态氧等）攻击DNA分子中的鸟嘌呤第8位碳原子而产生的一种氧化性加合物,它是活性氧基团引起的DNA氧化损伤修饰产物之一。     

小鼠二苯基吖啶的DNA加合物（32）￣p－后标记分析：初步测定最初的遗传毒理代谢物及其对生物标志物浓度的作用

小鼠二苯基吖啶的ＤＮＡ加合物（３２）￣ｐ－后标记分析：初步测定最初的遗传毒理代谢物及其对生物标志物浓度的作用Ｊ．Ｒｏｈｅｔａｌ含氮的有机化物在高温分解期间形成氮－杂环芳香族（ＮＨＡ）化合物，为广泛的环境污染物。在烟草冷凝物、合成燃料、汽油发动机的废气...     

DNA加合物检测方法研究进展

每年,人类都将新合成数以千计的化学物质用于生产、生活,并最终排放到环境当中,其中,许多化学物质可能具有遗传毒性。如何对这些物质进行监测和评价是一项十分艰难而重要的工作。随着研究的深入,人们提出应用大分子(蛋白质、RNA、DNA)加合物来研究其遗传毒性,其中DNA加合物由于意义重大而成为多学科的研究热点。DNA加合物就是亲电性的化学物质或其代谢产物与生物体内的DNA共价相连形成的复合体,是DNA化学损伤最重要和最普遍的形式。DNA加合物形成后,一旦逃避了自身的修复,就可能成为致突变、致畸、致癌的启动因子。所以,DNA加合物既可以作为接触标志物,反映毒物在靶部位的效应剂量,又可以作为效应标志物,反映DNA的损伤程度。     

大气颗粒有机提取物所致小鼠DNA加合物与微核的相关关系研究

目的 研究不同污染地区大气颗粒有机提取物（EOM）所致小鼠DNA损伤与细胞遗传效应改变的关系。方法 采用^32P后标记法研究各点大气颗粒有机提取物（EOM）对DNA的共价修饰作用,用微核实验检测染色体的断裂情况。结果 不同污染地区大气EOM所致小鼠DNA加合物形成与微核形成之间均存在相关关系。结论 大气污染物中的EOM所致小鼠内遗传物质DNA的损伤可能导致细胞遗传效应的改变。     

Environmental tobacco smoke is just as damaging to DNA as mainstream smoke.

This study demonstrates the ability of tar isolated from environmental tobacco smoke (ETS) to nick DNA in mammalian cells. Solutions of ETS tar behave similarly to aqueous solutions of cigarette tar from mainstream smoke. Both solutions contain the tar semiquinone radical, and this radical associates with the DNA in viable rat alveolar macrophages. Solutions of tar from ETS cause single-strand DNA breaks in rat thymocytes in proportion to the amount of tar present, until a plateau is reached. ETS tar solutions, like mainstream tar solutions, produce hydrogen peroxide. Hydrogen peroxide appears to be an essential component of the mechanism by which both ETS tar and mainstream tar cause DNA damage in rat thymocytes, as catalase substantially protects against DNA damage. Glutathione also protects against DNA nicking by both ETS and mainstream tar solutions by scavenging radicals and/or oxidants. The chelator diethylenetriamine pentaacetic acid also provides partial (40%) protection. The studies demonstrate that the water-soluble components of ETS tar can enter cells, associate with, and then nick DNA.     

White blood cell DNA adducts in a cohort of asthmatic children exposed to environmental tobacco smoke

Purpose  

Exposure to environmental tobacco smoke (ETS) leads to molecular damage in the form of DNA adducts. While lung cancer risk is higher among African Americans compared to White Americans, a few studies have tested for racial differences in DNA adducts among children exposed to ETS. The purpose of this study was to test whether African American children have higher DNA adducts levels compared to White children adjusted for ETS exposure.     

Importance of exposure to gaseous and particulate phase components of tobacco smoke in active and passive smokers

Summary The uptake of tobacco smoke constituents from gaseous and particulate phases of mainstream smoke (MS), inhaled by smokers, and of environmental tobacco smoke (ETS), breathed in by non-smokers, was investigated in two experimental studies. Tobacco smoke uptake was quantified by measuring carboxyhemoglobin (COHb), nicotine and cotinine in plasma and urine and the data obtained were correlated with urinary excretion of thioethers and of mutagenic activity. An increase in all biochemical parameters was observed in smokers inhaling the complete MS of 24 cigarettes during 8 h, whereas only an increase in COHb and, to a minor degree, in urinary thioethers was found after smoking the gas phase of MS under similar conditions. Exposure of non-smokers to the gaseous phase of ETS or to whole ETS at similar high concentrations for 8 h led to identical increases in COM, plasma nicotine and cotinine as well as urinary excretion of nicotine and thioethers which were much lower than in smokers. Urinary mutagenicity was not found to be elevated under either ETS exposure condition. As shown by our results, the biomarkers most frequently used for uptake of tobacco smoke (nicotine and cotinine) indicate on the one hand the exposure to particulate phase constituents in smoking but on the other hand the exposure to gaseous phase constituents in passive smoking. Particle exposure during passive smoking seems to be low and a biomarker which indicates ETS particle exposure is as yet not available. These findings emphasize that risk extrapolations from active smoking to passive smoking which are based on cigarette equivalents or the use of one biomarker (e.g. cotinine) might be misleading.     

Gestation stage-specific oxidative deoxyribonucleic acid damage from sidestream smoke in pregnant rats and their fetuses

Transplacental exposure to environmental tobacco smoke (ETS) is a possible cancer risk factor in offspring. The authors exposed pregnant Sprague-Dawley rats to a relevant dose of ETS (1 mg/m3) from gestation day 4 to days 16 or 21. They then assayed tissues for levels of 8-oxo-2'-deoxyguanosine (8-oxo-dG), a marker of oxidative deoxyribonucleic acid damage. ETS exposure ending on gestation day 16 resulted in statistically significant increases in 8-oxo-dG in maternal liver and kidney and in fetal kidney. On gestation day 21, there were significant 8-oxo-dG increases in fetal liver and brain. These gestational stage- and tissue-specific increases of 1.2- to 1.4-fold are similar to the putative relative increases in risk of human cancers related to ETS.     

Perinatal environmental tobacco smoke exposure in rhesus monkeys: critical periods and regional selectivity for effects on brain cell development and lipid peroxidation

Perinatal environmental tobacco smoke (ETS) exposure in humans elicits neurobehavioral deficits. We exposed rhesus monkeys to ETS during gestation and through 13 months postnatally, or postnatally only (6-13 months). At the conclusion of exposure, we examined cerebrocortical regions and the midbrain for cell damage markers and lipid peroxidation. For perinatal ETS, two archetypal patterns were seen in the various regions, one characterized by cell loss (reduced DNA concentration) and corresponding increases in cell size (increased protein/DNA ratio), and a second pattern suggesting replacement of larger neuronal cells with smaller and more numerous glia (increased DNA concentration, decreased protein/DNA ratio). The membrane/total protein ratio, a biomarker of neurite formation, also indicated potential damage to neuronal projections, accompanied by reactive sprouting. When ETS exposure was restricted to the postnatal period, the effects were similar in regional selectivity, direction, and magnitude. These patterns resemble the effects of prenatal nicotine exposure in rodent and primate models. Surprisingly, perinatal ETS exposure reduced the level of lipid peroxidation as assessed by the concentration of thiobarbituric acid reactive species, whereas postnatal ETS did not. The heart, a tissue that, like the brain, has high oxygen demand, displayed a similar but earlier decrease (2-3 months) in lipid peroxidation in the perinatal exposure model, whereas values were reduced at 13 months with the postnatal exposure paradigm. Our results provide a mechanistic connection between perinatal ETS exposure and neurobehavioral anomalies, reinforce the role of nicotine in these effects, and buttress the importance of restricting or eliminating ETS exposure in young children.     

Sidestream tobacco smoke exposure acutely alters human nasal mucociliary clearance.

Nasal mucociliary clearance (NMC) is a biomarker of nasal mucosal function. Tobacco smokers have been shown to have abnormal NMC, but the acute effect of environmental tobacco smoke (ETS) on nonsmokers is unknown. This study evaluated acute tobacco smoke-induced alterations in NMC in 12 healthy adults. Subjects were studied on 2 days, separated by at least 1 week. Subjects underwent a 60-min controlled exposure at rest to air or sidestream tobacco smoke (SS) (15 ppm CO) in a controlled environmental chamber. One hour after the exposure, 99mTc-sulfur colloid was aerosolized throughout the nasal passage and counts were measured with a scintillation detector. Six out of 12 subjects showed more rapid clearance after smoke exposure than after air exposure, and 3/12 had rapid clearance on both days. However, substantial decreases in clearance occurred in 3/12 subjects, all of whom had a history of ETS rhinitis. In two subjects, more than 90% of the tracer remained 1 hr after tracer administration (2 hr after smoke exposure). Understanding the basis for biologic variability in the acute effect of tobacco smoke on NMC may advance our understanding of pathogenesis of chronic effects of ETS.     

1,N(2)-propanodeoxyguanosine adduct formation in aortic DNA following inhalation of acrolein

Recent reports indicate that many of the cytotoxic and health-threatening components of environmental tobacco smoke (ETS) reside in the vapor phase of the smoke. We have reported previously that inhalation of 1,3-butadiene, a prominent vapor phase component of ETS, accelerates arteriosclerotic plaque development in cockerels. In this study we asked whether inhaled acrolein, a reactive aldehyde that is also a prominent vapor-phase component of ETS, damages artery-wall DNA and accelerates plaque development. Cockerels inhaled 0, 1, or 10 ppm acrolein mixed with HEPA-filtered air for 6 hr. Half were killed immediately (day 1 group) for detection of the stable, premutagenic 1,N(2)-propanodeoxyguanosine acrolein adduct (AdG3) in aortic DNA via a (32)P-postlabeling/HPLC method, and half were killed after 10 days (day 10 group) for indirect assessment of adduct repair. In the day 1 group, acrolein-DNA adducts were 5 times higher in the 1 and 10 ppm groups than in HEPA-filtered air controls. However, in the day 10 group, adduct levels in the 1 and 10 ppm acrolein groups were reduced to the control adduct level. For the plaque studies, cockerels inhaled 1 ppm acrolein (6 hr/day, 8 weeks), mixed with the same HEPA-filtered air inhaled by controls. Plaque development was measured blind by computerized morphometry. Unlike butadiene inhalation, acrolein inhalation did not accelerate plaque development. Thus, even though repeated exposure to acrolein alone has no effect on plaque size under the exposure conditions described here, a single, brief inhalation exposure to acrolein elicits repairable DNA damage to the artery wall. These results suggest that frequent exposure to ETS may lead to persistent artery-wall DNA damage and thus provide sites on which other ETS plaque accelerants can act.