香烟侧流烟雾引起的DNA分子氧化损伤

目的：通过研究环境烟草烟雾的侧流烟雾（ETSS）对DNA分子的氧化损伤，探讨环境烟草烟雾（ETS）的遗传毒性效应及其分子机制。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ETSS染毒后的DNA中8－OHdG进行定量检测，通过气质联用法（GC－MS）对香烟烟雾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：ETSS的颗粒物和挥发性有机物污染物123种和84种，有机元素7种，其中醌类，多酚等化合物具有自氧化作用，不需要任何生物活性系统，在体外就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－OHdC ,结论：ETSS对DNA具有氧化能力，体现了直接的遗传毒性效应，8－OHdG是DNA氧化损伤较好的效应标志物。     

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。     

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。     

香烟烟雾对A549与A549-R细胞的氧化损伤

目的探讨hOGG1基因低表达对香烟烟雾作用下细胞氧化损伤效应的影响。方法不同浓度香烟烟雾暴露A549细胞和hOGG1基因低表达的A549-R细胞,MTT实验检测两种细胞存活率,彗星实验观察两种细胞DNA损伤,荧光法测定两种细胞内活性氧(ROS)含量,高效液相色谱-电化学法(HPLC-ECD)检测细胞基因组DNA中8-羟基脱氧鸟苷(8-OHdG)的含量。结果随着香烟烟雾暴露浓度的增加,两种细胞的存活率均下降,且A549-R细胞IC50显著小于A549细胞,差异有统计学意义(P<0.05);两种细胞ROS生成量与香烟烟雾浓度呈剂量-效应关系,当香烟烟雾浓度≥1.25支/升时,A549-R细胞ROS含量显著高于A549细胞(P<0.05);不同香烟烟雾浓度下,A549-R细胞拖尾率、尾长、OTM值均大于A549细胞,差异有统计学意义(P<0.05);A549细胞与A549-R细胞基因组DNA8-OHdG含量随香烟烟雾浓度的增加而升高,当香烟烟雾浓度为2.5支/升和5支/升时,A549-R细胞8-OHdG含量显著高于A549细胞(P<0.05)。结论香烟烟雾可导致A549细胞与A549-R细胞的氧化损伤,hOGG1基因低表达可增加A549-R细胞对香烟烟雾引起的氧化损伤的敏感性。     

硒强化沙棘油对吸烟所致氧化性损伤的保护作用

硒强化沙棘油对吸烟所致氧化性损伤的保护作用崔香丽高应王惠芸柳湘吸烟不仅危害吸烟者本人，对环境也产生污染。香烟的烟雾中和烟油中均含有大量自由基。它们在促癌过程中起着重要的作用。沙棘油富含维生素Ｅ和β－胡萝卜素，硒可提高谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）...     

苯乙烯-DNA加合特性的研究

目的 研究苯乙烯的DNA加合特性。方法 采用紫外光谱移动法测定苯乙烯－7，8－氧化物（SO）、苯乙烯、苯乙醇酸（MA）、苯乙醛酸（PGA）、苯乙烯巯基尿酸（UMA）和DNA的加合反应；以^32P后标记法研究SO－DNA加合物；以气相色谱－质谱、核磁共振研究SO－DAN加合物的结构。结果 苯乙烯、MA、PGA和UMA不与DNA发生加合反应；SO分别在DNA脱氧鸟苷碱基上的O^6位、N^2位形成6种加合物。结论 苯乙烯进入机体后，通过其活性中间代谢物SO与DNA起加合作用，SO攻击DNA脱氧鸟苷碱基上的O^6位、N^2位形成加合物，如果在细胞复制前所形成的DNA加合物没有被修复或者被错误修复的话，就有可能导致基因突变，产生化学损伤。苯乙烯的其他代谢物未见此效应。     

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。     

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。     

Increased urinary excretion of 8-hydroxydeoxyguanosine in engine room personnel exposed to polycyclic aromatic hydrocarbons

Background: Previous investigations indicate that engine room personnel on ships are exposed to polycyclic aromatic hydrocarbons (PAH) from oil and oil products, with dermal uptake as the major route of exposure. Several PAH are known carcinogens and mutagens.

Aims: To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxy-guanosine (8OHdG), in engine room personnel, and to study the association between 8OHdG and 1-hydroxypyrene (1OHP), a biological marker for PAH exposure.

Methods: Urine samples were collected from engine room personnel (n = 36) on 10 Swedish and Norwegian ships and from unexposed controls (n = 34) with similar age and smoking habits. The exposure to oils, engine exhaust, and tobacco smoke 24 hours prior to sampling was estimated from questionnaires. The urinary samples were frozen for later analyses of 8OHdG and 1OHP by high performance liquid chromatography.

Results: Excretion in urine of 8OHdG (adjusted to density 1.022) was similar for controls (mean 18.0 nmol/l, n = 33), and for those who had been in the engine room without skin contact with oils (mean 18.7 nmol/l, n = 15). Engine room personnel who reported skin contact with oil had increased excretion of 8OHdG (mean 23.2 nmol/l, n = 19). The difference between this group and the unexposed controls was significant. The urinary levels of ln 1OHP and ln 8OHdG were significantly correlated, and the association was still highly significant when the effects of smoking and age were accounted for in a multiple regression analysis.

Conclusion: Results indicate that exposure to PAH or possibly other compounds from skin contact with oils in engine rooms may cause oxidative DNA damage.

     

Why and how should we measure oxidative DNA damage in nutritional studies? How far have we come?

Free radicals and other reactive species are constantly generated in vivo and cause oxidative damage to DNA at a rate that is probably a significant contributor to the age-related development of cancer. Agents that decrease oxidative DNA damage should thus decrease the risk of cancer development. That is, oxidative DNA damage is a "biomarker" for identifying persons at risk (for dietary or genetic reasons, or both) of developing cancer and for suggesting how the diets of these persons could be modified to decrease that risk. This biomarker concept presupposes that we can measure oxidative damage accurately in DNA from relevant tissues. Little information is available on whether oxidative DNA damage in blood cells mirrors such damage in tissues at risk of cancer development. Measurement of 8-hydroxylated guanine (eg, as 8-hydroxy-2'-deoxyguanosine; 8OHdG) is the commonest method of assessing DNA damage, but there is no consensus on what the true levels are in human DNA. If the lowest levels reported are correct, 8OHdG may be only a minor product of oxidative DNA damage. Indeed, 8OHdG may be difficult to measure because of the ease with which it is formed artifactually during isolation, hydrolysis, and analysis of DNA. Mass spectrometry can accurately measure a wide spectrum of DNA base damage products, but the development of liquid chromatography-mass spectrometry techniques and improved DNA hydrolysis procedures is urgently required. The available evidence suggests that in Western populations, intake of certain fruit and vegetables can decrease oxidative DNA damage, whereas ascorbate, vitamin E, and beta-carotene cannot.     

Cigarette smoke potentiates the DNA-damaging effect of manmade mineral fibers

Epidemiological and experimental studies suggest that manmade mineral fibers (MMMFs) have DNA-damaging and carcinogenic properties. To investigate the hypothesis that cigarette smoke can potentiate MMMF-induced DNA damage, we exposed isolated calf thymus DNA to cigarette smoke condensate and/or three different types of MMMFs: rockwool, glasswool, and ceramic fibers. As an index of DNA damage, the hydroxyl radical-generated formation of 8-hydroxydeoxyguanosine (8OHdG) from deoxyguanosine (dG) was used. All the three fiber types, as well as cigarette smoke condensate alone, caused hydroxylation of dG residues in DNA, and, when smoke was combined with each of the different fibers, rockwool caused a synergistically increased formation of 8OHdG. We suggest that 1) iron-containing MMMFs such as rockwool are able to enhance synergistically cigarette smoke-induced DNA-damage and 2) this damage is caused by hydroxyl radicals.     

Urinary malondialdehyde and 8-hydroxydeoxyguanosine as potential markers of oxidative stress in industrial art glass workers

Previous epidemiological studies have indicated that industrial art glass workers have increased mortality risks for certain types of cancer and for cardio-and cerebrovascular disease. To test the hypothesis that increased oxidative stress might contribute to these increased mortality risks, the urinary levels of the lipid peroxidation product, malondialdehyde (MDA), and the oxidative DNA adduct, 8-hydroxydeoxyguanosine (8OHdG) were determined in 343 workers (230 men and 113 women) from the art glass industry in the southeast of Sweden. Of the study subjects, 199 (181 men and 18 women) were engaged in the process of glass production and were regarded as exposed, whereas the remainders performed clerical, warehouse and other service work and were regarded as unexposed. One hundred and sixteen were smokers (75 men and 41 women) and 215 were non-smokers (142 men and 73 women). The findings indicate that (a) exposure to industrial art glass work per se does not cause any major oxidative stress as measured by urinary levels of MDA and 8OHdG, (b) the effects from smoking per se are limited to increased lipid peroxidation among men, and (c) joint exposure to industrial art glass work and smoking may cause increased lipid peroxidation among men and increased DNA hydroxylation among both men and women. While these findings provide no evidence for increased oxidative stress due to industrial art glass work per se, the increased 8OHdG excretion in workers who smoke may be associated with a higher risk of developing free radical-dependent degenerative disease including cancer     

太阳光及紫外线照射诱发M13mp2噬菌体DNA产生8-OHdG的作用

[目的 ]分析太阳光及长波紫外线 (UVA)、中波紫外线 (UVB)诱发Ml3mp2噬菌体DNA产生 8 羟基脱氧鸟苷(8 OHdG)的作用。 [方法 ]用太阳光、UVA和UVB照射处理M13mp2噬菌体样品 ,以HPLC EC检测DNA样品中的 8 OHdG。 [结果 ] 1、3、5h太阳光照射和 2 8、10 8、2 5 0、5 0 0kJ/m2 剂量UVA照射后的样品均可检测到 8 OHdG含量增加 ,并存在与照射剂量的依存关系。较高剂量 (2 6kJ/m2 )UVB照射也可引起 8 OHdG的产生。 [结论 ]太阳光照射致M13mp2噬菌体突变作用中 ,存在DNA的氧化损伤 ,主要是UVA的作用。     

组织细胞对氧化损伤的敏感性及修复能力的研究

目的：探讨体内多种组织细胞对DNA氧化损伤效应的敏感性及损伤后的自身修复能力。方法：以H2O2作为氧化损伤剂，对离体的小鼠肝，肾，脾细胞进行染毒，用慧星试验观察各种细胞的DNA氧化损伤效应与修复动力学改变。结果：H2O2能诱导三种细胞DNA氧化损伤，其损伤的敏感性依次为：脾细胞＞肾细胞＞肝细胞，修复试验显示肝细胞修复能力最强，修复时间最短，脾细胞次之，而肾细胞在2h内几乎无修复。结论：体内组织细胞对氧化损伤的敏感性及修复能力差异很大，彗星试验在一定程度上可以检测外源化学物的DNA氧化损伤效应。