乙双吗啉处理小鼠白细胞DNA-加合物水平变化的研究

目的研究乙双吗啉处理小鼠白细胞DNA-加合物水平的变化规律。方法整体动物实验:①整体动物实验方法:纯系615小鼠80只随机分为乙双吗啉1、2和4mg剂量处理组及对照组,处理组给予相应剂量乙双吗啉灌胃,每日1次,连续2个月,对照组同时给予等量蒸馏水,观察处理不同时间小鼠外周血象及骨髓象的变化;②外周血白细胞DNA的提取及定量;③DNA-加合物的测定;④外周血白细胞微核率的测定和骨髓染色体畸变率测定。离体实验方法:①离体实验体系的建立;②外周血白细胞DNA的提取及定量;③DNA-加合物测定。结果①整体动物实验:乙双吗啉处理小鼠白血病发病率明显增高,其发病率分别为:1mg组15%,2mg组25%,4mg组25%,与对照组相比差异有非常显著性(P<0.01),处理组白血病小鼠总体发病率为21.7%;乙双吗啉处理小鼠外周血白细胞DNA-加合物较对照组升高(P<0.01);乙双吗啉处理小鼠外周血白细胞微核率和骨髓染色体畸变率较对照组升高(P<0.01);②离体实验:乙双吗啉可使小鼠白细胞DNA-加合物升高,与对照组比差异有非常显著性(P<0.01)。结论乙双吗啉可诱发小鼠白细胞DNA-加合物水平升高。

The expression of PAH-DNA adducts in lung tissues of Xuanwei female lung cancer patients

Objective:The coal-fired pollution in Xuanwei area has been considered to be local main reason for high incidence of female lung cancers.The aim of the study was to investigate the expression of PAH-DNA adducts in lung tissues of Xuanwei female lung cancer patients, and to explore the relationship between the large number of coal-fired pollution PAHs materials and the high incidence of Xuanwei female lung cancers.Methods:We totally collected each 20 cases of Xuanwei female lung cancer patients, Xuanwei male lung cancer patients, non-Xuanwei female lung cancer patients and collected each 10 cases of Xuanwei, non-Xuanwei female patients with benign lung lesions.The cancer tissues, adjacent cancer tissues and normal lung tissues were collected in lung cancer patients and only the normal tissues were collected in benign lung lesion patients.There were total 80 cases and 200 tissues.Using immunofluorescence, we detected the expression of PAH-DNA adducts in each group.Image pro-plus 6.0 software was used to analyze the images and did part quantified analysis.SPSS 13.0 statistical software was used to analyze the data.Results:The positive expressions of PAH-DNA adducts in lung cancer tissues, adjacent cancer tissues and normal lung tissues of Xuanwei female lung cancer patients were 90%, 80% and 65%, respectively.They were higher than the positive expressions of PAH-DNA adducts in Xuanwei male lung cancer patients (35%, 30% and 30%) and non-Xuanwei female lung cancer patients (20%, 15% and 10%; P<0.01).The expression of PAH-DNA adducts in lung tissues of Xuanwei female benign lung lesion patients (70%) was higher than that in non-Xuanwei female benign lung lesion patients (10%).With the direction changing from cancer tissues, adjacent cancer tissues to normal lung tissues, the expression of PAH-DNA adducts was decreased but had no statistical difference (P>0.05).Conclusion:The expression of PAH-DNA adducts in lung tissues of Xuanwei females was higher than that in Xuanwei males and non-Xuanwei females.

Antioxidative potential of a combined therapy of anti TNFα and Zn acetate in experimental colitis

AIM:To evaluate whether combination therapy with antitumour necrosis factor α (TNFα) antibody and Zn acetate is beneficial in dextran sodium sulphate (DSS) colitis.METHODS:Colitis was induced in CD1-Swiss mice with 5% DSS for 7 d.The experimental mice were then randomised into the following subgroups:standard diet + DSS treated (induced colitis group);standard diet + DSS + subcutaneous 25 μg anti-TNFα treated group;Zn acetate treated group + DSS + subcutaneous 25 μg anti-TNFα;standard diet + DSS + subcutaneous 6.25 μg anti-TNFα treated group and Zn acetate treated group + DSS + subcutaneous 6.25 μg anti-TNFα.Each group of mice was matched with a similar group of sham control animals.Macroscopic and histological features were scored blindly.Homogenates of the colonic mucosa were assessed for myeloperoxidase activity as a biochemical marker of inflammation and DNA adducts (8OH-dG) as a measure of oxidative damage.RESULTS:DSS produced submucosal erosions,ulcers,inflammatory cell infiltration and cryptic abscesses which were reduced in both groups of mice receiving either anti-TNFα alone or combined with zinc.The effect was more pronounced in the latter group (vs Zn diet,P < 0.02).Myeloperoxidase activity (vs controls,P < 0.02) and DNA adducts,greatly elevated in the DSS fed colitis group (vs controls,P < 0.05),were significantly reduced in the treated groups,with a more remarkable effect in the group receiving combined therapy (vs standard diet,P < 0.04).CONCLUSION:DSS induces colonic inflammation which is modulated by the administration of anti-TNFα.Combining anti-TNFα with Zn acetate offers marginal benefit in colitis severity.

Leptin influences estrogen metabolism and increases DNA adduct formation in breast cancer cells

Objective: The elevated incidence of obesity has been paralleled with higher risks of breast cancer. High adiposity increases leptin secretion from adipose tissue, which in turn increases cancer cell proliferation. The interplay between leptin and estrogen is one of the mechanisms through which leptin influences breast carcinogenesis. An unbalanced estrogen metabolism increases the formations of catechol estrogen quinones, DNA adducts, and cancer mutations. This study aims to investigate the effect of leptin on some estrogen metabolic enzymes and DNA adduction in breast cancer cells.Methods: High performance liquid chromatography(HPLC) was performed to analyze the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine. Reporter gene assay, real time reverse transcription polymerase chain reaction(real time RT-PCR), and Western blot were used to assess the expression of estrogen metabolizing genes and enzymes: Cytochrome P-4501B1(CYP1B1), Nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase1(NQO1), and Catechol-O-methyl transferase(COMT).Results: Leptin significantly increased the DNA adducts 4-OHE1[E2]-1-N3 adenine and 4-OHE1[E2]-1-N7 guanine.Furthermore, leptin significantly upregulated CYP1B1 promoter activity and protein expression. The luciferase promoter activities of NQO1 and m RNA levels were significantly reduced. Moreover, leptin greatly reduced the reporter activities of the COMT-P1 and COMT-P2 promoters and diminished the protein expression of COMT.Conclusions: Leptin increases DNA adduct levels in breast cancer cells partly by affecting key genes and enzymes involved in estrogen metabolism. Thus, increased focus should be directed toward leptin and its effects on the estrogen metabolic pathway as an effective approach against breast cancer.

Ecogenotoxicology in earthworms： A review

Pollutant dynamics and bioavailability greatly differ in soil and aquatic systems. Therefore, specific approaches and models are needed to assess the impact of soil contamination to terrestrial ecosystems. Earthworms among other soil invertebrates have received more attention because of their ecological importance. They represent a dominant part of the soil biomass and are soil engineers regulating important soil processes, notably fertilization. The release in soils of pollutants known for their persistence and/or their toxicity is a concern. Exposure of terrestrial species to pollutants that may alter genomic function has become an increasing topic of research in the last decade. Indeed, genome disturbances due to genetic and epigenetic mechanisms may impair growth, as well as reproduction and population dynamics in the long term. Despite their importance in gene expres- sion, epigenetic mechanisms are not yet understood in soil invertebrates. Until now, pollutant-induced changes in genome expression in natural biota are still being studied through structural alteration of DNA. The first biomarker relating to genotoxicant exposure in earthworms from multi-contaminated soils reported is DNA adducts measurements. It has been replaced by DNA breakage measured by the Comet assay, now more commonly used. Functional genomic changes are now being explored owing to molecular ＂omic＂ technologies. Approaches, objectives and results are overviewed herein. The focus is on studies dealing with genotoxicity and populational effects established from environmentally-relevant experiments and in situ studies [Current Zoology 60 （2）： 255-272, 2014].