硫芥诱导小鼠染色体畸变和微核形成作用的研究

目的　研究硫芥对中国仓鼠肺成纤维细胞 (chinesehamsterfibroblastcellline ,CHL)染色体的诱变作用及对小鼠骨髓微核率的影响。方法　培养CHL细胞 (±S9) ,以不同浓度硫芥处理 2 4h后常规方法制备染色体 ,观察畸变类型并计算畸变率。KM小白鼠皮下注射硫芥染毒 ,2 4h后处死动物 ,取双侧股骨 ,行骨髓涂片和姬姆萨染色 ,计数含微核嗜多染红细胞(polychromaticerythrocyte ,PCE)数。结果　硫芥处理的CHL细胞染色体畸变率显著增加 ,出现裂隙、断裂、缺失、多倍体等多种类型畸变 ,并呈量效依赖趋势。S9不影响硫芥诱导的CHL细胞染色体畸变形式和畸变率。与对照组比较 ,注射硫芥小鼠骨髓PCE微核率显著增加 (P <0 .0 1) ,硫芥剂量越大 ,微核形成率越高。结论　硫芥能直接诱发细胞染色体损伤。     

Comparison of genomic damage caused by 5-nitrofurantoin in young and adult mice using the in vivo micronucleus assay

The antibiotic 5-nitrofurantoin (5-NF) has been used widely for the treatment of urosepsis in children during the last 20 years. Recent experimentation suggests the need for reevaluating its genotoxic potential. Because of possible differences in the metabolism and clearance of 5-NF in young and adult animals, we conducted a study to determine whether micronuclei caused by 5-NF were age-related. The in vivo micronucleus (MN) assay was performed on 3- and 8-week-old mice given single intraperitoneal injections of 5, 10, and 50 mg/kg 5-NF. Blood samples from the tail vein were taken before injection (baseline) and at 48, 96, 168, and 336 hr (2 weeks) after the treatment. One thousand reticulocytes were analyzed for micronuclei from each animal. Compared to similar baseline values for young and adult mice, 5-NF caused a significant increase in MN frequency in both age groups. The mean MN frequency in the young animals was higher than in the adult animals for each dose and sampling time. MN frequencies remained significantly elevated in young animals even 2 weeks after exposure to 5-NF. The results of the study confirm the genotoxic potential of 5-NF in young and adult animals, and indicate that young animals are more sensitive to the genotoxic effects of 5-NF than adult mice and that the response in young mice persists for a significantly longer time. These findings may be related to poorly developed mechanisms of xenobiotic detoxification and renal elimination in young animals.     

大鼠肝彗星试验与骨髓微核试验评价结果比较研究

目的 梳理国家药物安全评价监测中心联合开展的大鼠多终点体内遗传毒性试验数据,比较大鼠肝彗星试验与骨髓微核试验结果的一致性和灵敏性。方法 试验分设阴性物质组、作用机制明确的遗传毒性阳性物质组、受试物组,阴性物质包括超纯水、0.9%氯化钠注射液、玉米油、0.5%羧甲基纤维素钠（CMC-Na）、5%蔗糖和聚山梨酯80,给药体积为10 mL·kg^-1;遗传毒性阳性物质包括200 mg·kg^-1甲磺酸乙酯（EMS）、40 mg·kg^-1N-乙基-N-亚硝基脲（ENU）、40 mg·kg^-1环磷酰胺、75 mg·kg^-1甲基苄肼、800 mg·kg^-1尿烷、75 mg·kg^-1对氯苯胺、40 mg·kg^-1 1,2-二溴-3-氯丙烷和10 mg·kg^-1秋水仙素;受试物包括100、300、1000 mg·kg^-1大黄素-8-O-β-D-葡萄糖苷,6.5、65.0、650.0 mg·kg^-1单蒽酮和6.5、65.0、650.0 mg·kg^-1大黄素甲醚。分别在实验0、24、45 hig给药1次,给药体积为10 mL·kg^-1。开展大鼠肝彗星试验和骨髓微核试验,计算每只动物的肝细胞刺猬细胞率和尾DNA百分含量（Tail% DNA）,以及每只动物的嗜多染红细胞（PCE）/总红细胞（ERY）比例和嗜多染红细胞微核（MNPCE）率。结果 大鼠肝彗星试验可有效检出DNA断裂剂,对多种烷化剂（甲磺酸乙酯、甲基苄肼和尿烷等）有较好的预测性,但对环磷酰胺和多倍体诱导剂不灵敏。大黄素-8-O-β-D-葡萄糖苷、单蒽酮和大黄素甲醚骨髓微核试验结果均为阴性。大黄素-8-O-β-D-葡萄糖苷在1 000 mg·kg^-1剂量下导致的肝Tail% DNA与0.5% CMC-Na组比较显著升高（P<0.05）;单蒽酮的肝彗星试验结果为明确阳性,剂量为650 mg·kg^-1时,单蒽酮可导致大鼠肝Tail% DNA显著升高（P<0.05）,且作用存在剂量相关性;大黄素甲醚的肝彗星试验结果为阴性。结论 大鼠肝彗星试验可与骨髓微核试验互补,有效检出主要作用于肝脏且亲电子性较强的遗传毒性化合物。     

汉防已甲素对小鼠遗传毒性的研究

通过精子畸形试验、微核实验及姐妹染色单体交换试验,进行了汉防己甲素对小鼠遗传毒性的研究。结果表明,汉防己甲素组的小鼠精子畸形率及小鼠骨髓细胞微核率显著增高,且存在剂量—反应关系。但小鼠姐妹染色单体交换频率的改变不显著。表明该药对实验动物具有遗传毒性。     

接触金属汞的工人淋巴细胞微核率和姊妹染色单体互换率的观察

用机械法可使菜籽粕中毒性质的丙基异硫氰酸酯由０．７１％降到０．２１％，脱除率为７０．４２％，可替代猪、鸡中部分豆饼、鱼粉、降低饲料成本９．５６％－１２．６９％，县地生产性能不良影响。这种脱毒菜籽粕在体重３５－６０ｋｇ阶段猪日粮中用量不宜超过２０％；在肉仔鸡日糖中用量可为１０％或１５％。     

Evaluation of the genetic damage to workers in a Greek shipyard

Shipyards are industrial areas where workers are likely exposed to environmental pollutants such as welding fumes, fine organic solvent and dye dust, that render the occupational environment a high risk one. Assessing the risk that workers are exposed to is a high critical factor in improving their working conditions. The present study aims to investigate the potential genetic damage to workers exposed to a harsh environment in a Greek shipyard. It is focused on assessing the percentage of induced micronuclei, as well as on changes in the various cell types of shipyard workers’ oral mucosa epithelium by implementing the buccal micronucleus cytome assay. Exposed workers appeared with statistically significant induced micronuclei as compared to office employees. Statistically, significant cell lesions were detected and are related to workers’ exposure to environmental conditions. The workers’ smoking habit contributed as well to the observed buccal epithelial cell alterations. The observed data signify the high-risk workers are exposed; resulting in the shipyard’s management the need to implement measures improving the working environment conditions and to reevaluate the workers’ personal protective equipment requirements.     

Case studies putting the decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping) into practice

Case studies covering carbonaceous nanomaterials, metal oxide and metal sulphate nanomaterials, amorphous silica and organic pigments were performed to assess the Decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping). The usefulness of the DF4nanoGrouping for nanomaterial hazard assessment was confirmed. In two tiers that rely exclusively on non-animal test methods followed by a third tier, if necessary, in which data from rat short-term inhalation studies are evaluated, nanomaterials are assigned to one of four main groups (MGs). The DF4nanoGrouping proved efficient in sorting out nanomaterials that could undergo hazard assessment without further testing. These are soluble nanomaterials (MG1) whose further hazard assessment should rely on read-across to the dissolved materials, high aspect-ratio nanomaterials (MG2) which could be assessed according to their potential fibre toxicity and passive nanomaterials (MG3) that only elicit effects under pulmonary overload conditions. Thereby, the DF4nanoGrouping allows identifying active nanomaterials (MG4) that merit in-depth investigations, and it provides a solid rationale for their sub-grouping to specify the further information needs. Finally, the evaluated case study materials may be used as source nanomaterials in future read-across applications. Overall, the DF4nanoGrouping is a hazard assessment strategy that strictly uses animals as a last resort.     

Induction of micronuclei following exposure to methylene di-phenyl diisocyanate: potential genotoxic metabolites.

Methylene di-phenyl diisocyanate (MDI) is used to make polyurethane products. The predominant occupational disease attributed to diisocyanates, including MDI, is asthma; however, the potential for genotoxicity has also been of concern. Diisocyanates are very reactive compounds that can undergo nonenzymatic hydrolysis to form methylenedianiline (MDA), or react under physiological conditions with primary amines to form ureas and/or with thiols to form labile thiol acid esters. MDA is a carcinogen in animals and a suspected carcinogen in humans. Brown Norway rats (BNR) were exposed to either 7 or 113 mg/m(3) MDI aerosol for 1 h/week x3 weeks and sacrificed 1 week later. Micronuclei (MN) formation was assessed from bone marrow polychromatic erythrocytes (PCE). A dose-dependent increase in the frequency of micronucleated polychromatic erythrocytes (MN-PCEs) was noted. In vitro exposure of Chinese hamster lung fibroblasts (V79) to MDA or MDI-thiol conjugates, but not to MDI, significantly increased the frequency of MN. MDI-thiol conjugate-exposed cell cultures did not have detectable levels of MDA. A significant increase in the number of V79 cells in metaphase, as well as the number of cells with precipitants within both the cytoplasm and nuclei, were noted in MDI-glutathione-exposed cultures. The results of this study indicate that MDI aerosol exposure can cause MN formation through either the hydrolysis of MDI to MDA or possibly the formation of thiol conjugates.     

三硝基甲苯(TNT)对人体外周血淋巴细胞微核率影响的研究

本文对54名TNT作业工人和20名病毒性肝炎患者及30名对照工人进行了外周血淋巴细胞微核率的观察。结果表明:TNT接触者微核率明显高于对照组;15年以上工龄组微核率明显高于1、4、8年工龄组;但TNT接触者与病毒性肝炎患者间无显著性差异。本文证实:TNT可以导致人体外周血淋巴细胞微核率的增高,引起染色体损害,长期接触其影响更大。     

Increased micronucleus frequency in phytohaemagglutinin-stimulated blood cells of patients with vitiligo

Background Vitiligo is a relatively common, acquired pigmentary disorder characterized by areas of depigmented skin resulting from loss of melanocytes in the epidermis. Although several hypotheses have been proposed for the aetiology and pathogenesis of vitiligo, the cause of vitiligo remains unclear. Objective To evaluate spontaneous micronucleus (MN) frequency using the cytokinesis block MN assay to determine damages at the DNA or chromosome level in phytohaemagglutinin (PHA)‐stimulated blood cells of patients with vitiligo and healthy control subjects. Methods Peripheral blood samples were obtained and cultured from 21 patients with vitiligo (mean age: 21.48 ± 9.78 years) and 21 age‐ and sex‐matched healthy control subjects (mean age: 21.52 ± 9.80 years). MN values were scored in binucleated cells obtained from whole‐blood cultures of patients and control subjects. Results MN frequencies (mean ± SD) in PHA‐stimulated blood cells of patients with vitiligo and control subjects were 0.94 ± 0.58 and 0.58 ± 0.32, respectively. Compared with control subjects, MN frequencies of patients with vitiligo were found significantly higher than those of the control subjects (P = 0.012). Conclusion Our results indicate unexpectedly some chromosomal/DNA damage in whole‐blood cultures of patients with vitiligo. We do not know, however, if these chromosome/DNA instabilities observed in the cells of vitiligo patients resulted from the cause or from the consequences of the disorder.