鼻咽癌组织中氧化性DNA损伤标志物8-硝基鸟嘌呤和8-羟基脱氧鸟苷的检测及与iNOS的关系

8-硝基鸟嘌呤（8-nitroguanine, 8-NitroG）和8-羟基脱氧鸟苷（8-hydroxy-2′-deoxyguanosine, 8-OHdG）是2个氧化性DNA损伤生物标志物,而诱导型一氧化氮合酶(iNOS)在病理状态下催化细胞合成与氧化性DNA损伤有关的 氧自由基NO.本研究通过检测鼻咽癌组织中8-NitroG、8-OHdG和iNOS的免疫反应强度,初步探究鼻咽癌的发生和发展是否与氧化性DNA损伤有关以及8-NitroG、8-OHdG与iNOS表达的关系.利用多克隆抗体8-NitroG和单克隆抗体8-OHdG、iNOS,采用双色荧光免疫组织化学方法检测鼻咽癌组织中8-NitroG、8-OHdG和iNOS的免疫反应,秩和检验统计学方法分析鼻咽癌和慢性咽炎鼻咽组织之间8-NitroG、8-OHdG和iNOS免疫反应强度的差异.结果显示,19例鼻咽癌组织细胞中,8-NitroG、8-OHdG和iNOS均为强免疫反应,8-NitroG和8-OHdG阳性率100%,iNOS阳性率94.7 %,与13例慢性咽炎组织比较差异显著(P.<0.05).结果提示,鼻咽癌的发生和发展与氧化性DNA损伤有关,其原因与炎症等病理刺激下鼻咽组织高表达的iNOS催化细胞合成氧自由基NO引起的8-NitroG和8-OHdG DNA损伤密切相关.另外,8-NitroG和8-OHdG有望成为辅助鼻咽癌诊断的生物标志物.     

DNA氧化损伤的免疫组织化学研究

采用目前公认的DNA氧化损伤标志物8-OHdG的单抗,利用LSAB法研究不同年龄组BALB/C小鼠胸腺和脾脏8-OHdG的生成水平,对免疫组织在衰老过程中DNA氧化损伤的水平进行免疫组织化学研究。以探讨免疫系统的自由基损伤对衰老的影响。结果表明,在胸腺,8-OHdG^ 细胞密度随增龄而增多,并主要位于髓质区;脾脏中的阳性细胞则无明显的增龄性变化,但胸染形态却存在明显差异。本研究结果显示,衰老过程中,免疫细胞内8-OHdG含量发生改变,免疫系统受到了氧自由基的损伤。8-OHdG可作为免疫老化过程中的一种生物标志。     

抗癌药顺铂对小鼠脑和肾组织DNA氧化损伤的检测分析

目的:探讨抗癌药顺铂(cisplatin)对小鼠脑和肾组织DNA的氧化损伤。方法:采用SABC法进行脑和肾组织8-OHdG的免疫组化染色。结果:顺铂给药组小鼠的大脑皮质和海马的毛细血管内皮细胞及肾小球毛细血管内皮细胞呈现8-OHdG免疫组化阳性反应,对照组小鼠在上述区域未见阳性反应细胞。结论:顺铂可引起大脑皮质和海马的毛细血管内皮细胞及肾小球毛细血管内皮细胞DNA的氧化损伤。     

基于胶体金的8-羟基-2′-脱氧鸟苷免疫层析试纸条北大核心CSCD

8-羟基-2′-脱氧鸟苷(8-hydroxy-2′-deoxyguanosine,8-OHdG)是评价DNA氧化损伤较灵敏和稳定的生物标志物。文中采用竞争法建立一种快速、灵敏检测8-OHdG的胶体金免疫层析试纸条。将样品垫(玻璃纤维素膜)、结合垫(玻璃纤维素膜)、硝酸纤维素膜和吸水垫依此粘贴在聚氯乙烯(polyvinyl chloride,PVC)底板上,构建试纸条。通过柠檬酸钠还原三水合四氯金酸制备胶体金(gold nanoparticles,AuNPs),8-OHdG配对的抗体(antibody,Ab)包被于AuNPs的外层(Ab coated AuNPs,Ab@AuNPs)作为探针。牛血清蛋白(bovine serum protein,BSA)与8-OHdG用碳二亚胺盐酸盐偶联制备人工抗原,作为检测线的包被抗原。羊抗鼠多抗(imunoglobulin G,IgG)作为质控线的包被抗体。对试纸条的硝酸纤维素膜、上样液的配方、金标抗体喷涂量等实验参数进行了优化。结果表明,硝酸纤维素膜(nitrocellulose film,NC)膜采用CN 95,上样液的最优配方为1%BSA+3%吐温-20+3%蔗糖+0.9%NaCl溶液,最适金标抗体喷涂量为4μL。利用试纸条在可见光下检测8-OHdG,根据检测线(test line,T线)和质控线(control line,C线)的显色强度对比,可初步判断尿液中8-OHdG的含量水平。并通过T线的灰度值计算尿液中的8-OHdG的浓度,检测限为2.55μg/L。该方法简单、快速且有较好的特异性,可检测人体尿液中的8-OHdG含量,以初步评价人体的健康状态。     

阿尔茨海默病患者血清P-tau-181、8-OHdG、Lp-PLA2水平与认知功能的关系及其预测价值分析

摘要 目的：探讨阿尔茨海默病（AD）患者血清磷酸化Tau蛋白-181（P-tau-181）、8-羟基脱氧鸟苷酸（8-OHdG）、脂蛋白相关磷脂酶A2（Lp-PLA2）水平与认知功能的关系及其预测价值。方法：选择2018年1月～2019年12月我院收治的AD患者90例作为AD组,血管源性痴呆（VD）患者90例作为VD组,同期于我院进行体检的健康者90例作为对照组,比较各组血清P-tau-181、8-OHdG、Lp-PLA2水平、蒙特利尔认知评估量表（MoCA）、简易智力状态检查量表（MMSE）、临床痴呆评定量表（CDR）评分,比较不同认知功能障碍程度AD患者血清P-tau-181、8-OHdG、Lp-PLA2水平,并分析各指标的相关性,应用ROC曲线分析血清P-tau-181、8-OHdG、Lp-PLA2水平对AD的预测价值。结果：AD组血清P-tau-181、8-OHdG、Lp-PLA2水平显著高于VD组和对照组（P＜0.05）,VD组和对照组血清P-tau-181、8-OHdG、Lp-PLA2水平比较无统计学差异（P>0.05）。AD组、VD组MoCA、MMSE评分显著低于对照组,CDR评分显著高于对照组（P＜0.05）,AD组和VD组MoCA、MMSE和CDR评分比较无统计学差异（P>0.05）。随着AD患者认知功能的降低,患者血清P-tau-181、8-OHdG、Lp-PLA2水平逐渐升高（P＜0.05）。Pearson相关性分析显示,AD患者血清P-tau-181、8-OHdG、Lp-PLA2与MoCA、MMSE评分呈负相关,与CDR评分呈正相关（P＜0.05）。ROC曲线分析显示,P-tau-181、8-OHdG、Lp-PLA2诊断AD的敏感度分别为88.55%、89.34%、89.77%,特异度分别为81.94%、82.56%、85.67%。结论：AD患者血清P-tau-181、8-OHdG、Lp-PLA2水平异常升高,其水平可以反映患者认知功能障碍程度,对AD的早期诊断和防治具有一定价值。     

2型糖尿病患者脂联素、8-OHdG表达及其与认知功能的相关性

本研究旨在探究老年2型糖尿病患者血浆脂联素、8-羟基脱氧鸟苷(8-OHdG)表达变化及其与认知功能的相关性,通过选取本院2016年2月至2017年2月收治的2型糖尿病患者作为研究对象,根据有无认知功能损害分为2组,并选取同期100名健康体检者。检查入组人群血浆脂联素、8-OHdG水平,并对临床资料进行分析。结果发现糖尿病患者血浆脂联素、8-OHdG水平高于健康人群(p0.05);糖尿病伴认知功能障碍患者血浆脂联素、8-OHdG水平高于糖尿病患者(p0.05)。糖尿病患者MMSE评分、MoCA评分、数字广度测验得分低于健康人群,连线测验完成时间高于人群(p0.05);糖尿病伴认知功能障碍患者MMSE评分、MoCA评分、数字广度测验得分低于糖尿病患者无认知功能障碍者,连线测验完成时间高于糖尿病患者无认知功能障碍者(p0.05)。经Spearman相关性分析,发现2型糖尿病患者MoCA评分与年龄、BMI、糖尿病病程、空腹血糖、HBA1c、血浆脂联素水平、血浆8-OHdG水平呈负相关,与受教育年限呈正相关(p0.05)。结果说明2型糖尿病伴认知功能障碍患者血浆脂联素、8-OHdG水平升高,且与患者认知功能呈负相关;临床中可通过检测血浆脂联素、8-OHdG水平,对糖尿病患者认知功能进行初步评估,以指导后续治疗。     

褪黑素缓解空肠黏膜上皮细胞氧化损伤的效果研究

肠道黏膜氧化损伤与畜禽的生长发育和腹泻等疾病的发生密切相关，而褪黑素作为一种吲哚胺类化合物，具有明显抗氧化保护作用。为探究褪黑素对肠黏膜上皮细胞氧化损伤时的保护作用，本研究选取原代小鼠空肠黏膜上皮细胞，利用硫酸亚铁和过氧化氢处理建立氧化损伤模型，并通过添加不同浓度的褪黑素预处理上皮细胞，检测细胞损伤、氧化产物、抗氧化酶和炎性相关细胞因子的表达变化。结果发现，硫酸亚铁和过氧化氢处理后，黏膜上皮细胞明显受损，丙二醛含量显著增加、抗氧化酶表达水平降低。而褪黑素能明显减轻细胞氧化损伤程度、抑制丙二醛的产生并增加抗氧化酶的表达。同时，褪黑素还能显著减少炎性因子白介素-6的表达，并增加趋化因子白介素-8的表达。因此，褪黑素可以缓解自由基增加诱发的空肠黏膜上皮细胞氧化损伤，并能够减轻细胞损伤引起的炎症反应。     

超氧化物歧化酶与氧化应激相关内耳疾病的研究进展

超氧化物歧化酶(SOD)作为细胞内氧自由基清除剂,能将O-2,催化生成O2和H2O2;与氧化应激相关的内耳疾病密切相关,对氧化应激引起的内耳毛细胞及听觉神经元损伤具有保护作用.本文从SOD的基因结构、一般理化特性、在内耳氧化损伤的作用、作为内耳基因治疗策略的应用前景进行综述.     

DNA氧化损伤8-羟鸟嘌呤与肿瘤的发生发展

有氧代谢有机体细胞无法避免活性氧(reactive oxygen species, ROS)的伤害。ROS会造成多种形式的DNA损伤,其中鸟嘌呤G的氧化产物8-羟鸟嘌呤(8-oxoG)是频度最高的一种DNA氧化损伤,由特异性的糖苷酶OGG1识别并开启碱基切除修复通路完成修复。8-oxoG如果没有及时修复,可能会在复制的过程中引入G:C配对到T:A配对的碱基颠换突变。因此8-oxoG的积累或OGG1修复功能异常被认为会影响基因功能,进而导致肿瘤或衰老相关疾病的发生,然而直接实验证据却极为有限。近年来一系列研究表明,8-oxoG倾向于产生在基因的调控区,在这种情形下,8-oxoG可视为一种表观遗传学修饰,而OGG1则是这一信息的特异性读取者,OGG1对底物的识别、结合或切除会引发DNA构象或组蛋白修饰的改变,进而引起基因表达的上调或下调。因此,除了潜在的遗传毒性,鸟嘌呤氧化损伤与肿瘤的关联与其通过表观遗传学机制引发基因表达的异常密切相关。本文对8-oxoG及修复酶OGG1与肿瘤发生发展的关联机制进行了分析与总结,旨在提示研究人员从新的视角解读DNA氧化损伤与肿瘤的关系,并为肿瘤的治疗提供新...     

氢气作为新型治疗气体的研究进展

氧化损伤是大多数疾病的共同病理生理基础,氢气作为一种新型的抗氧化物质,可选择性中和毒性最强的活性氧——羟基自由基(·OH),这可能会成为预防和治疗疾病的重要手段。目前,关于氢气的医学研究逐渐升温,氢气可治疗的疾病类型已达到近百种,在研究对象上有细胞学研究、器官水平的研究和整体动物研究,并已初步涉及到临床研究。尽管如此,有关氢气效应的基础生物学机制仍有待深入探索。现结合最新研究进展,对氢气生物学效应、分子机制、摄入方式以及临床应用等方面做简要概述。     

Evaluation of a urinary multi-parameter biomarker set for oxidative stress in children, adolescents and young adults

The involvement of reactive oxygen species (ROS) and oxidative stress in pediatric diseases is an important concern, but oxidative stress status in healthy young subjects and appropriate methods for its measurement remain unclear. This study evaluated a comprehensive set of urinary biomarkers for oxidative stress in healthy children, adolescents and young adults. Results show that urinary excretion of acrolein-lysine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), nitrite/nitrate and pentosidine were highest in the youngest subjects and decreased to constant levels by early adolescence. Urinary acrolein-lysine, 8-OHdG, nitrite/nitrate and pentosidine showed significant inverse correlations with age, but pyrraline did not change significantly with age. No significant differences in biomarkers were apparent between males and females. Younger subjects grow rapidly and sustain immune activation, and are probably exposed to high concentrations of ROS and nitric oxide. Consequently, they are more vulnerable to oxidation of lipids, proteins, DNA and carbohydrates. Normal reported values in this study are a basis for future studies of disease mechanisms involving oxidative stress and for future trials using antioxidant therapies for oxidative stress-related diseases in the pediatric field.     

Evaluation of a urinary multi-parameter biomarker set for oxidative stress in children,adolescents and young adults

The involvement of reactive oxygen species (ROS) and oxidative stress in pediatric diseases is an important concern, but oxidative stress status in healthy young subjects and appropriate methods for its measurement remain unclear. This study evaluated a comprehensive set of urinary biomarkers for oxidative stress in healthy children, adolescents and young adults. Results show that urinary excretion of acrolein–lysine, 8-hydroxy-2′-deoxyguanosine (8-OHdG), nitrite/nitrate and pentosidine were highest in the youngest subjects and decreased to constant levels by early adolescence. Urinary acrolein–lysine, 8-OHdG, nitrite/nitrate and pentosidine showed significant inverse correlations with age, but pyrraline did not change significantly with age. No significant differences in biomarkers were apparent between males and females. Younger subjects grow rapidly and sustain immune activation, and are probably exposed to high concentrations of ROS and nitric oxide. Consequently, they are more vulnerable to oxidation of lipids, proteins, DNA and carbohydrates. Normal reported values in this study are a basis for future studies of disease mechanisms involving oxidative stress and for future trials using antioxidant therapies for oxidative stress-related diseases in the pediatric field.     

Impact of modernization on oxidative stress among indigenous populations in northern Laos

Objectives

To explore the impact of modernization on oxidative stress during a momentous health transition process, we investigated differences in oxidative stress among the indigenous populations of villages in northern Laos with different levels of modernization.

Methods

We conducted a cross-sectional study of 380 adults in three villages with different levels of modernization. Three biomarkers related to oxidative stress were measured: urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-isoprostane concentrations (both measured by liquid chromatography–tandem mass spectrometry), and blood telomere length (measured with qPCR). We examined associations between village-level modernization and oxidative stress-related biomarkers in a multilevel analysis including a random effect and covariates.

Results

The geometric means of urinary 8-OHdG and 8-isoprostane concentrations were 2.92 and 0.700 μg/g creatinine, respectively, in our study population. Higher urinary 8-OHdG concentrations and shorter telomeres were observed in participants from the more modernized villages, whereas urinary 8-isoprostane concentrations did not differ significantly among villages.

Conclusions

Our findings imply that modernization-induced changes in lifestyle may increase oxidative DNA damage. Baseline levels of oxidative lipid damage are expected to be high in the indigenous populations of northern Laos. Assessments of oxidative stress may provide valuable insights into the mechanisms of health transition in specific populations.     

Exercise-induced oxidatively damaged DNA in humans: evaluation in plasma or urine?

Physical exercise can induce oxidative damage in humans. 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a widely known biomarker of DNA oxidation, which can be determined in blood and urine. The aim of the present study was to compare these two biological fluids in terms of which is more suitable for the estimation of the oxidative damage of DNA by measuring the concentration of 8-OHdG one hour after maximal exercise by enzyme immunoassay. The concentration of 8-OHdG increased with exercise only in plasma (p?<?0.001), and values differed between exercise tests in both plasma and urine (p?<?0.05). In conclusion, plasma appears to be more sensitive to exercise-induced 8-OHdG changes than urine and, hence, a more appropriate medium for assessing oxidative damage of DNA, although the poor repeatability of the measurement needs to be addressed in future studies     

Serum cholesterol positively associated with oxidative DNA damage: a propensity score-matched analysis

Oxidative DNA damage pathogenically links to some major diseases. This study aimed to comprehensively assess the association between serum total cholesterol (TC) and oxidative DNA damage based on propensity score matching (PSM) method. A total of 407 participants chronically exposed to arsenic via drinking water from China were enrolled. Oxidative DNA damage was determined with urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG). Serum TC was classified into favourable TC (FTC, TC <5.18?mmol/L) and unfavourable TC (NFTC, TC ≥5.18?mmol/L) categories. Multivariable generalised linear regression model was applied to examine the association. Of 407 participants, 125 pairs with FTC and NFTC subjects were matched using PSM. Urinary 8-OHdG/creatinine levels in NFTC were significantly higher than those in FTC category (p?=?.002). As compared to the counterparts, additional adjusted log-transformed 8-OHdG/creatinine increase was observed in NFTC for unmatched (β?=?0.12, p?=?.052) and matched (β?=?0.17, p?<?.001) participants, respectively. We also detected obviously increased log-transformed urinary 8-OHdG/creatinine with per interquartile range raise of serum TC either in unmatched (β?=?0.10, p?=?.007) or matched (β?=?0.16, p?=?.003) subjects. In conclusion, serum TC was independently associated with oxidative DNA damage. Our findings provided new insights on the health promotion of lipids relevant to the early warning of diseases due to oxidative DNA damage.     

Increased DNA Oxidation and Decreased Levels of Repair Products in Alzheimer's Disease Ventricular CSF

Abstract : One of the leading etiologic hypotheses regarding Alzheimer's disease (AD) is the involvement of free radical-mediated oxidative stress in neuronal degeneration. Although several recent studies show an increase in levels of brain DNA oxidation in both aging and AD, there have been no studies of levels of markers of DNA oxidation in ventricular CSF. This is a study of levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), the predominant marker of oxidative DNA damage, in intact DNA and as the "free" repair product that results from repair mechanisms. Free 8-OHdG was isolated from CSF from nine AD and five age-matched control subjects using solidphase extraction columns and measured using gas chromatography/mass spectrometry with selective ion monitoring. Intact DNA was isolated from the same samples and the levels of 8-OHdG determined in the intact structures. Quantification of results was carried out using stable isotope-labeled 8-OHdG. By using this sensitive methodology, statistically significant elevations ( p < 0.05) of 8-OHdG were observed in intact DNA in AD subjects compared with age-matched control subjects. In contrast, levels of free 8-OHdG, removed via repair mechanisms, were depleted significantly in AD samples ( p < 0.05). Our results demonstrate an increase in unrepaired oxygen radical-mediated damage in AD DNA as evidenced by the increased presence of 8-OHdG in intact DNA and decreased concentrations of the free repair product. These data suggest that the brain in AD may be subject to the double insult of increased oxidative stress, as well as deficiencies in repair mechanisms responsible for removal of oxidized bases.     

Levels of 8-hydroxy-2'-deoxyguanosine in DNA of white blood cells from workers highly exposed to asbestos in Germany

Asbestos fibers have genotoxic effects and are a potential carcinogenic hazard to occupationally exposed workers. The ability of inhaled asbestos fibers to induce the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the DNA of white blood cells (WBC) of workers highly exposed at the workplace has been studied. The 8-OHdG adduct level of asbestos-exposed workers was significantly increased (p<0.001) compared to that in the control group in all three years of the study. Asbestos-exposed individuals showed a mean value of 2.61+/-0.91 8-OHdG/10(5) dG (median 2.49, n=496) in 1994-1995, 2.96+/-1.10 8-OHdG/10(5) dG (median 2.76, n=437) in 1995-1996 and 2.55+/-0.56 8-OHdG/10(5) dG (median 2.53, n=447) in 1996-1997. For the control subjects, a mean of 1.52+/-0.39 (median 1.51, n=214) was determined. The results indicate that human DNA samples from exposed individuals contain between 1.7 times and twice the level of oxidative damage relative to that found in control samples in all 3 years of the study. The studies presented here show that asbestos exposure can result in oxidative DNA damage. Our data confirm that oxidative DNA damage occurs in the WBC of workers highly exposed to asbestos fibers, thus supporting the hypothesis that asbestos fibers damage cells through an oxidative mechanism. These in vivo findings underline the importance of oxidative damage in asbestos-induced carcinogenesis and highlight the need for exploring the molecular basis of asbestos-induced diseases, and for more effective diagnosis, prevention and therapy of mesothelioma, lung cancer and pulmonary fibrosis. In addition, preventive and therapeutic approaches using antioxidants may be relevant.     

8-Hydroxyguanosine formed in human lung tissues and the association with diesel exhaust particles

Diesel exhaust particles consist of various organic chemicals, heavy metals, and carbon particles. Knowledge of the fate of organic chemicals and carbon particles in the lungs is important to determine the mechanisms responsible for lung tumors. In the present study, diesel particle extracts were found to show mutagenicity for YG3003, a sensitive strain to some oxidative mutagens, as well as other mutant strains, and those of lung tissues obtained from lung cancer patients exhibited potent mutagenicity. Formation of 8-hydroxyguanosine (8-OHdG) as a biomarker of oxidative damage was analyzed with in vitro and in vivo assay systems. The 8-OHdG was detected in all 22 cases of lung tissues with carcinomas tested and their levels increased with the increasing age of the patients, suggesting a correlation between age and the presence of carbon particles in lung tissues. Therefore, the formation of 8-OHdG due to diesel exhaust particles was investigated via intratracheal injections into mice. 8-OHdG formation was elevated when carboneceous particles, after removal of organic chemicals with various solvents, were administered to mice, but it was not elevated when polyaromatic compounds such as benzo[a]pyrene, 1,8-dinitropyrene, and 1-nitropyrene were used in the same procedure in mice. The carboneceous particles were formed from a giant particle that was aggregated by micro-particles with diameters of 1.47 +/- 1.34 to 1.05 +/- 0.83 microm. These results suggest that carboneceous particles, but not mutagens and carcinogens, promote the formation of 8-OHdG, and that as a mechanism, alveolar macrophages may be involved in oxidative damage. The oxidative damage may be due to the fact that the mutation is involved with the generation of a hydroxyl radical during phagocytosis, and the hydroxyl radical leads to hydroxylation at the C-8 position of the deoxyguanosine residue in the DNA.     

Methacryloxylethyl Cetyl Ammonium Chloride Induces DNA Damage and Apoptosis in Human Dental Pulp Cells via Generation of Oxidative Stress

The polymerizable antibacterial monomer methacryloxylethyl cetyl ammonium chloride (DMAE-CB) has provided an effective strategy to combat dental caries. However, the application of such material raises the question about the biological safety and the question remains open. The mechanism of this toxic action, however, is not yet clearly understood. The present study aims at providing novel insight into the possible causal link between cellular oxidative stress and DNA damage, as well as apoptosis in human dental pulp cells exposed to DMAE-CB. The enhanced formation of reactive oxygen species and depletion of glutathione, as well as differential changes in activities of superoxide dismutase, glutathione peroxidase, and catalase in DMAE-CB-treated cells indicated oxidative stress. By using substances that can alter GSH synthesis, we found that GSH was the key component in the regulation of cell response towards oxidative stress induced by DMAE-CB. The increase in oxidative stress-sensitive 8-Oxo-2''-deoxyguanosine (8-OHdG) content, formation of γ-H₂AX and cell cycle G1 phase arrest indicated that DNA damage occurred as a result of the interaction between DNA base and ROS beyond the capacities of antioxidant mechanisms in cells exposed to DMAE-CB. Such oxidative DNA damage thus triggers the activation of ataxia telangiectasia-mutated (ATM) signaling, the intrinsic apoptotic pathway, and destruction of mitochondrial morphology and function.