大鼠气管上皮细胞体内—体外转化模型的研究

本研究建立了大鼠气管上皮细胞体内－体外转化模型，大鼠气管内滴注苯并芘，三天后处死大鼠，消化气管上皮细胞，接种于无血清完全培养基。细胞形成集落后，换为选择培养基继续培养五周，统计转化率。结果显示，２５ｍｇ／ｋｇ和５０ｍｇ／ｋｇ的苯并芘可诱导大鼠气管上皮细胞转化及微核增加，用同样方法研究了煤焦沥青提取物，结果表明，剂量为８ｍｇ／ｋｇ和２５ｍｇ／ｋｇ的煤焦沥青提取物能明显诱导大鼠气管上皮细胞转化。     

甲醛接触工人的外周血淋巴细胞微核研究

甲醛（ＦＡ）在多种体外诱变测试中呈阳性，啮齿动物吸入甲醛蒸气后引起鼻腔鳞状上皮细胞癌＾（１，２），接触人群的肿瘤发病主有升高趋势，因此对甲醛接触人群进行简单有效的遗传毒理学的生物学监测是十分必要的，本次研究微核测试的结果证实，８０名平均工龄，１２年甲醛接触者的外周血淋巴细胞微核细胞率较对照组有极显著的增加（Ｐ〈０．０１），接触组吸烟人群较对照组吸烟人群的微核细胞率有极明显的增高（Ｐ〈０．０１），接     

Genotoxicity evaluation of metformin and glimepiride by micronucleus assay in exfoliated urothelial cells of type 2 diabetes mellitus patients

Micronucleus (MN) assay was performed on the exfoliated urothelial cells to detect the genotoxic effects of the anti-hyperglycemic drugs, metformin and glimepiride in T2DM patients and to use it as a biomarker for DNA damage by assessing the frequency of micronuclei in the exfoliated urothelial cells. A total of 201 subjects (147 T2DM patients & 54 Normal cases) were selected from diverse age groups (25–75 years) and the mean MN frequency was examined per 1000 cells in all the subjects. Relative to the control group (5.02 ± 1.01), an increased MN frequency was observed in females (26.15 ± 2.15) when compared to males (23.08 ± 2.09) in T2DM patients. Further analysis showed that there was a profound increase in the number of MN in the patients using metformin alone (23.02 ± 4.44), or combination of metformin & glimepiride (24.98 ± 2.87) than to the subjects using glimepiride alone (17.52 ± 3.28). It has been proven by this simple, reliable and non-invasive method that metformin has a potential role in causing genotoxicity and that the MN observed in exfoliated urothelial cells could be used as a reliable biomarker in monitoring the genotoxic risk of the anti-hyperglycemic drugs.     

双微体型微核产生的分子机制

微核(micronuclei,MN),也叫卫星核,是真核生物细胞中的一种异常结构,是基因组不稳定在细胞中的一种表现形式,根据其内容物成分来源分为“染色体型微核”和染色体外元件形成的微核,即“双微体型微核”,这两种形式微核在同一细胞中是独立产生和存在的.双微体是在肿瘤细胞中常见的染色体外元件,因此,了解双微体型微核产生的分子机制将有助于更清楚这些染色体外结构是如何保留在细胞内或者排出细胞外的.该文就双微体型微核产生的分子机制及微核的生物学活性作一综述.     

Evaluation of teratogenicity and genotoxicity induced by kramecyne (KACY)

Kramecyne (KACY), a polymer isolated from Krameria cytisoides Cav, has anti-inflammatory, anti-nociceptive, anti-arthritic and anti-ulcerogenic properties. As a part of standard preclinical safety tests, the present study sought to determine potential developmental toxicity (in female rats) and genotoxicity (in male mice) of KACY. Pregnant female rats were divided into six groups: the negative control (vehicle), the positive control (250?mg/kg of acetylsalicylic acid (ASA)), and four experimental groups (50, 250, 500 and 1000?mg/kg of KACY). To evaluate genotoxicity by in vivo micronuclei (MN) and sister chromatid exchange (SCE) tests, male mice were divided into five groups: the negative control (vehicle), the positive control (1.5 and 2.5?mg/kg of doxorubicin for MN and SCE, respectively), and three experimental groups (50, 500 and 1000?mg/kg of KACY). All treatments were administered by oral gavage. A slight maternal toxicity was evidenced by lower weight gain for rats receiving 500 and 1000?mg/kg of KACY, but no fetal malformations were found. However, there were less live fetuses/litter and greater post-implantation loss/litter at these two doses. Manifestations of developmental toxicity were limited to a higher rate of skeletal alterations. The MN tests did not evidence genotoxicity or cytotoxicity. KACY caused a slightly but significantly increased frequency of SCE. Although KACY-treated rats had skeletal alterations, these apparently were not caused by a mechanism of genotoxicity. Furthermore, the same administration in adult male mice did not produce genotoxicity. Hence, KACY herein proved to be safe for rats during the period of organogenesis.     

Evaluation of the cyto/genotoxicity profile of oxime K048 using human peripheral blood lymphocytes: An introductory study

This study investigates the effects of oxime K048 (730, 200, and 7.3 nM) on the viability and chromosome stability of human peripheral blood lymphocytes (PBLs) after a 30 min exposure in vitro. Cytotoxicity was tested by a viability assay with ethidium bromide and acridine orange. For the evaluation of the genotoxic potential, we used comet assays, cytokinesis-blocked micronucleus (CBMN) assay, and chromosome aberration (CA) analysis. We found acceptable cytotoxicity for K048 (9.7 ± 2.1% non-viable PBL at highest concentration vs. 7.3 ± 2.5% in control; apoptosis dominated over necrosis). Overall primary DNA damage was low and not significantly different from controls. The hOGG1-comet assay showed a slight increase in the level of oxidative DNA damage. In oxime treated PBLs, we found 13–19 MN compared to 15 MN in control cultures. The frequencies and types of CA in oxime-treated PBLs did not significantly differ from controls. K048 showed acceptable biocompatibility at the level of cell viability and chromatin/chromosome integrity. Since no increase in secondary genome damage was detected, the primary DNA lesions may have resulted from treatment-induced cell stress, subsequently becoming repaired and not fixed as chromosome aberrations. The toxicity profile of K048 should be further studied and compared with other clinically relevant oximes.     

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.     

南京“5.7” 192Ir源放射事故患者的生物剂量估算

目的 用3种方法估算南京"5.7" ¹⁹²Ir源放射事故患者的生物剂量,为核与辐射事故受照者的临床救治提供剂量资料。方法 受照后第5天采集患者外周血,分别进行外周血淋巴细胞染色体"双着丝粒+环"("dic+r")畸变分析、胞质分裂阻滞微核(CBMN)分析、核质桥(NPB +FHC)分析,并估算生物剂量。用双着丝粒畸变在细胞间的泊松分布情况检验照射的均匀性。结果3种方法估算的该患者受到的一次全身等效剂量分别为"dic+r"畸变分析1.51 Gy (95% CI 1.40~1.61),CBMN 分析1.47 Gy (95% CI 1.36~1.60),NPB+FHC分析1.30 Gy(95% CI 1.00~1.60)。泊松分布检验结果显示,该患者"dic+r"畸变偏离泊松分布,受到了不均匀照射。结论 外周血淋巴细胞染色体"dic+r"畸变分析、CBMN分析、NPB+FHC分析均是有效的生物剂量估算手段,对本例急性局部不均匀照射患者估算的一次全身等效剂量与临床诊断结果相符。     

Protective effects of Hibiscus tiliaceus L. methanolic extract to V79 cells against cytotoxicity and genotoxicity induced by hydrogen peroxide and tert-butyl-hydroperoxide

Plants of the genus Hibiscus thrives produce a diversity of molecules with bioactive properties. In a previous study of Hibiscus tiliaceus L. methanolic extract (HME) using bacteria and yeast, as test media, it has been shown that HME strongly inhibited the mutagenic action of H₂O₂ or tert-butyl-hydroperoxide (t-BHP). Here, our interest is to evaluate the genotoxicity and the antigenotoxic/antimutagenic properties of HME using oxidative challenge with H₂O₂ and t-BHP in V79 cells. We determined cytotoxicity using clonal survival assay; evaluated DNA damage using the comet assay and the micronucleus test in binucleated cells besides of the lipid peroxidation degree and the reduced glutathione content. We examined the ability of HME in quenching hydroxyl radical by means of a HPLC-based method utilizing the hypoxanthine/xanthine oxidase assay. At concentrations ranging from 0.001 to 0.1 mg/mL, HME was not cytotoxic, genotoxic or mutagenic. Treatment with non-cytotoxic concentrations of HME increased cell survival after H₂O₂ and t-BHP exposure and prevented DNA damage. The pre-treatment with HME also was able to decrease the mutagenic effect of these genotoxins, evaluated using the micronucleus test. HME prevented the increase in lipid peroxidation and decrease in GSH content in response to the oxidative challenge. Therefore, the ability in preventing against H₂O₂- and t-BHP-induced GSH depletion and lipid peroxidation was probably a major contribution to the cytoprotective effects. Moreover, HME acts as a hydroxyl radical scavenger. In summary, HME did not have a harmful or inhibitory effect on the growth of V79 cells and presented antioxidant activity, consequently, both antigenotoxic and antimutagenic effects against oxidative DNA damage.     

大蒜、大蒜绿茶合剂对MNNG诱发实验性胃癌及癌前病变PBL微核率的影响

 本文研究大蒜、大蒜绿茶合剂对MNNG诱发大鼠胃癌及癌前病变过程中PBL微核率的影响。结果显示，MNNG组（MG）MNF在10月与16月时无明显差异，但较对照组（CG）始终显着增高（P<0.001）,胃癌及癌前病变均高于CG（P<0.001）,癌前病变明显低于胃癌（P<0.001）,预防组（PG）、治疗1（TGⅠ）与Ⅱ组（TGⅡ）皆低于MG（P<0.001）,PG在16月较10月时显着降低（P<0.001）,与TGⅠ无明显区别，而TGⅡ较PG10月时差异明显（P<0.005）,但与PG16月时和TGⅡ无差异。证明MNNG的致突变、致癌变性可持续作用，大蒜、绿茶具有明显的抗突变、抗癌变效果，微核先于胃癌出现于癌前病变，从而检测PBL微核可作为胃癌危险和早期的新标志。