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     

微核实验评价碳化硅陶瓷的潜在致突变性

目的通过微核实验检测自制碳化硅陶瓷对小鼠的致突变性以评价其生物相容性。方法将小鼠分成高、中、低剂量组及阴、阳性对照组,并与纯钛作比较,每组10只,共80只,按1ml/20g体重口服同剂量的浸提液,生理盐水作为阴性对照,阳性诱变剂:注射用环磷酰胺(CP)(75mg/kg)作为阳性对照,24小时后处死小鼠,观察P/N值。结果各实验组的微核率与阴性对照比较,无显著差异,并与纯钛组相近。结论自制碳化硅对小鼠无致突变性。     

雷藤氯内酯醇对大鼠生精细胞微核形成的影响

本文采用体内给药及体外培养大鼠睾丸曲细精管特定阶段的方法,研究了男性抗生育药雷公藤活性化合物雷藤氯内酯醇(T_4)对生精细胞微核形成的影响.结果表明,大鼠po抗生育剂量的T_4 50μg·kg~(-1)·d~1,4 wk,其微核发生率与阴性对照组相比无明显升高;体外曲细精管培养液中0.5ng·ml~1的T_4未导致微核率增加,而1.0和2.0 ng·ml~1的T_4使微核率显著升高,2.0和3.0ng·ml~(-1)的T_4在体外导致不同程度的细胞毒性作用,本文用生殖细胞减数分裂过程中微核的形成来检验化学物质对染色体的损伤是一个敏感的方法.在体抗生育剂量下T_4未导致微核率明显升高,离休实验中大剂量的T_4才能造成大鼠生精细胞微核率明显升高。     

miR-146a和miR-196a2前体区遗传多态性与焦炉工人遗传损伤的关系

目的 探讨miR-146a和miR-196a2前体区遗传多态位点rs2910164 G＞C和rs11614913 T＞C与焦炉工遗传损伤的关联性.方法 于2010年9月至10月,选取湖北省武汉市某焦化厂工龄在1年以上,无肿瘤,无吸烟习惯的焦炉作业工人,共575名.收集一般人口学资料并采集外周静脉血和尿液;采用胞质分裂阻滞试验计算外周血淋巴细胞的微核率来评价染色体损伤的程度;采用TaqMan探针对miR-146a前体区rs2910164 G＞C和miR-196a2前体区rs11614913 T＞C多态位点进行分型分析;采用三明治ELISA测定血浆中苯并[a]芘二氢二醇环氧化物-白蛋白(BPDE-白蛋白)加合物的浓度;并进行数据分析,并计算频率比(FR)及其95％ CI值.结果 共纳入575名工人.与携带野生型rs2910164 GG基因型的工人的外周血淋巴细胞微核率(4.02±3.09)相比,携带rs2910164CC基因型工人的微核率(4.38±3.46)增加(FR=1.18,95％CI:1.04～1.34),且有明显的等位基因剂量-效应关系(P趋势=0.025).按研究对象不同特征分层后,发现男性(FR=1.11,95％ CI:1.02～ 1.20)、不饮酒(FR=1.07,95％ CI:1.00 ～1.14)、工龄＜20年(FR=1.12,95％CI:1.03 ～ 1.22)和低BPDE-白蛋白水平组(FR=1.11,95％CI:1.02～1.21)中,rs2910164C等位基因与微核率的增加具有等位基因剂量-效应关系(P趋势分别为0.011、0.044、0.006和0.020).此外,与携带rs11614913TT基因型的工人(3.90±3.32)相比,携带rs11614913 TC基因型工人的外周血淋巴细胞微核率增加(4.27±2.91)(FR=1.12,95％CI:1.02 ～ 1.23).以同时携带rs2910164 GG及rs11614913TT基因型的工人组作为对照,同时携带rs2910164CC与rs11614913 CC基因型个体的外周血淋巴细胞微核率(5.32±4.94)是对照组(3.75±3.01)的1.51(1.21 ～1.89)倍.结论 miR-146a前体区域rs2910164C等位基因及miR-196a2前体区域rs11614913 C等位基因与焦炉工遗传损伤水平增加有关.     

Buccal micronucleus cytome assay in primary school children: A descriptive analysis of the MAPEC_LIFE multicenter cohort study

Background

Recent data support the hypothesis that genetic damage occurring early in life during childhood can play an important role in the development of chronic diseases in adulthood, including cancer.

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.