体内Pig-a基因突变试验组合评估丁香酚的遗传毒性

目的 采用大鼠3天染毒与体内Pig-a基因突变试验、彗星试验和微核试验组成的试验组合,评价丁香酚的体内遗传毒性。方法 雄性SD大鼠连续3天灌胃给予丁香酚,剂量为241.25mg/kg·bw(低)、482.5mg/kg·bw(中)、965.0mg/kg·bw(高),另设阳性对照组(N-乙基-N-亚硝基脲)和空白对照组。在第0、7、14、29天收集尾部静脉血进行体内Pig-a基因突变试验,检测样本中红细胞及网织红细胞突变率;在末次灌胃6h后收集尾部静脉血进行彗星试验;在末次灌胃36h后收集尾部静脉血进行外周血微核试验。结果 体内Pig-a基因突变试验中,各组间各时间点外周血突变红细胞和突变网织红细胞率差异均无统计学意义;彗星试验中,各组间彗星尾长和Tail-DNA%差异无统计学意义,但中、高剂量组Olive尾矩分别为6.42μm和8.35μm,与空白对照组比较差异有统计学意义,且呈剂量反应关系;微核试验中,高剂量组外周血网织红细胞微核率为0.45%,与空白对照组比较差异有统计学意义。结论 在本实验条件下,丁香酚在较高剂量下可能具有一定的遗传毒性。     

使用体内遗传毒性综合测试体系评价顺铂的遗传毒性

目的 使用大鼠体内遗传毒性综合测试体系全面评价顺铂的遗传毒性,为顺铂临床应用提供重要依据。方法 雄性SD大鼠（150～160 g）25只,每组5只。溶剂对照组为0.9%生理盐水,顺铂剂量组分别为0.125、0.25、0.5、1 mg/kg.bw,均按5 ml/kg.bw腹腔注射连续28 d染毒。于试验第0、14、28、42、56、84、112 d进行外周血Pig - a基因突变试验;于试验第0、4、28 d进行外周血微核试验;于试验第4、28 d给药后4 h进行外周血彗星试验。主要遗传毒性指标使用ANOVA进行假设检验,使用Dunnett - t进行剂量组和对照组之间的比较（检验水准 α= 0.05,双侧）。结果 Pig - a基因突变试验,0.250～1.000 mg/kg.bw组RBCs突变率和RETs突变率均有升高,与对照组比较差异有统计学意义。外周血微核试验,0.500～1.000 mg/kg.bw组RET微核率均有显著升高,与对照组比较差异有统计学意义;彗星试验,0.500～1.000 mg/kg.bw组尾部DNA含量均有显著增加,与对照组比较差异有统计学意义。结论 顺铂体内重复染毒具有引起DNA 损伤、基因突变、染色体断裂形成的遗传毒性,且在本次研究中顺铂的未观察到遗传毒性的最大剂量（NOGEL）为0.125 mg/kg.bw。     

焦炉工外周血淋巴细胞遗传物质损伤水平的研究

目的　评价焦炉作业环境接触多环芳烃对焦炉工外周血淋巴细胞遗传物质的损伤。方法　应用彗星试验和外周血淋巴细胞胞质分裂阻滞微核检测法 ,评价 13 7名焦炉工和 50名非职业多环芳烃暴露对照人群外周血淋巴细胞DNA和染色体损伤水平 ;测定其尿中 1 羟基芘水平 ,评价个体多环芳烃暴露内剂量 ;收集个人职业史、年龄、性别、吸烟和饮酒状况等信息。结果　焦炉工尿中 1 羟基芘水平为 (5.76± 1.0 4) μmol/molCr ,明显高于对照组 [(0 .70± 0 .3 2 ) μmol/molCr]。焦炉工外周血淋巴细胞微核率和彗星尾矩分别为 8.0‰ (0 .0‰～ 3 0 .0‰ )和 2 .0 9(0 .3 1～ 75.41) ,均高于对照组 [3 .5‰ (0 .0‰～13 .0‰ )、1.0 5(0 .11～ 6.63 ) ] ,差异有显著性 (P <0 .0 5)。对照组中 ,吸烟个体彗星尾矩为 1.44(0 .2 3～6.63 ) ,高于不吸烟个体 [0 .81(0 .11～ 3 .47) ] ,差异有显著性 (P <0 .0 5)。按焦炉作业工龄将 13 7名焦炉工分为 0 .5～、16.0～和 2 2 .0～ (年 ) 3组 ,校正了年龄、性别、吸烟、饮酒和尿中 1 羟基芘水平后 ,焦炉工外周血淋巴细胞彗星尾矩分别为 1.3 4 (0 .3 1～ 3 7.84)、2 .3 2 (0 .49～ 52 .97)和 3 .2 0 (0 .45～ 75.41) ,有随焦炉作业工龄增加而增加的趋势。结论　在现有多环芳烃暴露水平     

温室土壤有机提取物遗传毒性研究

[目的]检测温室土壤中有机提取物的遗传毒性作用. [方法]以小鼠为实验动物,共分5组:阴性对照组(二甲亚砜)、阳性对照组(环磷酰胺)及土壤有机提取物低、中、高剂量组,染毒剂量分别为5、15和30g土壤干重/(kg小鼠体重·d),染毒方式为每日灌胃1次,连续染毒4周.用胞质分裂阻滞微核细胞试验和彗星试验分别检测有机提取物所致小鼠外周血淋巴细胞的染色体损伤作用和外周血细胞的DNA损伤作用. [结果]有机提取物剂量与微核率具有较明显的剂量-效应关系,显著高于阴性对照组;随着有机提取物作用剂量的增加,彗星尾长、尾部DNA含量和Olive尾矩显著升高. [结论]温室土壤中有机提取物可以诱使小鼠发生染色体和DNA损伤.     

溴酸盐的遗传毒性

目的 探讨臭氧消毒饮用水副产物溴酸盐的遗传毒性。方法 采用Ames试验、UDS试验和微核试验，从基因水平、DNA水平和染色体水平对臭氧消毒副产物溴酸盐的遗传毒性进行研究。结果与阴性对照组相比，副产物溴酸盐不能使组氨酸缺陷型鼠伤寒沙门菌回复突变增加，但可使大鼠肝细胞程序外DNA合成增加和小鼠骨髓嗜多染红细胞微核形成率增加。结论 臭氧消毒副产物溴酸盐可能具有DNA及染色体水平的遗传毒性。     

3种溴虫腈制剂对小鼠淋巴细胞DNA的损伤作用

[目的]对溴虫腈农药的普通制剂、纳米制剂、纳米功能化制剂进行遗传毒性研究,为纳米农药制剂的开发应用提供参考依据。[方法]每个受试物分4.84、9.68、19.36mg/kg3个剂量组及1个对照组,每组6只动物,雌雄各半。一次性腹腔注射给药,24h后,用单细胞凝胶电泳技术检测3种制剂对小鼠外周血淋巴细胞DNA的损伤作用。采用CASP软件分析彗星图像,得出彗星头部和尾部DNA百分含量、彗星尾长、尾矩和Olive尾矩5个指标。[结果]在上述剂量条件下,3种制剂处理组检出DNA损伤的指标与对照组之间差异显著(P<0.01),DNA的损伤程度符合剂量-效应关系。在相同剂量条件下,纳米制剂、纳米功能化制剂与普通制剂间表现出极显著性差异(P<0.01),而纳米制剂与纳米功能化制剂的检测指标间差异无显著性(P>0.05)。[结论]溴虫腈具有遗传毒性,同一剂量条件下纳米制剂和纳米功能化制剂的遗传毒性要明显小于普通制剂的遗传毒性。     

Assessment of Genotoxicity in Gonads, Liver and Gills of Zebrafish (Danio rerio) by Use of the Comet Assay and Micronucleus Test after In Vivo Exposure to Methyl Methanesulfonate

Since generative tissues are a link between the generations, the detection of genetic damage in testis and ovary of fish is conductive to elucidating the relationship between genotoxicity and impairment of reproduction. In the current study, exposure of zebrafish to methyl methanesulfonate over two weeks caused concentration dependent genotoxic effects in gonads, liver and gills using the alkaline comet assay. Likewise, the micronucleus frequency was elevated in all of these organs. Thus, the comet assay and the micronucleus test proved appropriate for the detection of genotoxicity in primary male and female gonad cells and histological sections of the gonads from zebrafish, respectively.     

Estimation of DNA Integrity in Blood Cells of Eastern Mosquitofish (Gambusia holbrooki) Inhabiting an Aluminium-Polluted Water Environment: an Alkaline Comet Assay Study

To estimate the impacts of an Al-contaminated aquatic environment on DNA integrity in the blood cells of eastern mosquitofish Gambusia holbrooki Girard 1859 inhabiting Lake Njivice (Island of Krk, Croatia), an evaluation using the alkaline comet assay was carried out. Genome integrity was studied in parallel with the same fish species inhabiting the nearby, unpolluted Lake Ponikve. The amount of DNA damage in cells was estimated from three different parameters: comet tail length as the extent of genetic material migration, tail intensity (% DNA in the comet tail) and tail moment. The results indicate the loss of genome integrity in blood cells of mosquitofish inhabiting Lake Njivice and the genotoxicity of this aquatic environment. Using the same assay, acute genotoxicity of contaminated water and sediment was evaluated and confirmed on fish, mouse and human blood cells treated ex vivo. Results of the present study indicate that the alkaline comet assay applied to fish blood cells is a valuable tool for determining the potential genotoxicity of water pollutants and confirm its usefulness in the evaluation of DNA damage in fish living in Al-polluted waters.     

Comet assay with the fish cell line rainbow trout gonad-2 for in vitro genotoxicity testing of xenobiotics and surface waters

The present study examines the potential of the comet assay using the rainbow trout gonad cell line-2 (RTG-2) as an in vitro indicator test for genotoxicity assessment of aquatic contaminants and native surface waters. Initially, the comet assay protocol was adapted to the RTG-2 cell line. An exposure period of 2 h was found to be optimal, because DNA damage decreased when exposure was prolonged. Then, the sensitivity of the comet assay with RTG-2 cells toward six genotoxic reference substances was evaluated. The lowest-observed-effect concentration values for the directly acting genotoxins, 4-nitroquinoline-N-oxide and N-methyl-N'-nitro-N-nitrosoguanidine, were in the low nanomolar range. The RTG-2 test system clearly was less sensitive for the indirectly acting genotoxins benzo[a]pyrene, nitrofurantoin, 2-acetylaminofluorene, and dimethylnitrosamine, despite the presence of xenobiotic metabolic capacities in RTG-2 cells. The two effect endpoints used, tail length (TL) and tail moment (TM), did not differ with respect to sensitivity, but the linearity of the concentration-response curve was better with TM than with TL. The overall reproducibility of the assay results was good. Finally, the applicability of the comet assay with RTG-2 cells for genotoxicity screening of native surface water samples was studied. The assay tolerated the use of nonsterile water samples and was able to detect genotoxic potentials in native water samples; that is, extraction and concentration of the samples were not needed. The results of the present study indicate the suitability of the comet assay with the fish cell line, RTG-2, as in vitro screen for detecting genotoxic potencies of xenobiotics and environmental samples.     

二甲基亚砜拮抗烹调油烟冷凝物遗传毒性的研究

目的研究二甲基亚砜(DMSO)对烹调油烟冷凝物(COFC)致人支气管上皮细胞遗传毒性作用的影响。方法采用永生化人支气管上皮细胞系BEAS-2B细胞,分为空白对照组、DMSO对照组、试剂对照组(0.1%乙醇)、COFC染毒组(50、100、150mg/L)和相应的DMSO保护组(0.5%DMSO)。采用单细胞凝胶电泳和微核、多核实验研究COFC的遗传毒性及DMSO对烹调油烟损伤的防护作用。结果COFC染毒组可引起细胞DNA断裂,细胞拖尾率、彗星尾部DNA含量、尾长、尾部面积和尾距增加,微核多核率升高,DMSO对以上损伤有显著的拮抗作用。结论COFC对人支气管上皮细胞具有明显的遗传毒性作用,而DMSO对此有抑制作用。     

Alkaline Comet Assay for Genotoxic Effect Detection in Neotropical Fish Prochilodus lineatus (Pisces, Curimatidae)

Toxicants on fish may induce genetic alterations that can be used as genotoxic markers. We evaluated DNA damage using alkaline comet assay applied on erythrocytes after in vivo exposure of Prochilodus lineatus to different concentrations of Cypermethrin (0.300, 0.150, 0.075 and 0.000 μg/L) as a probable chemical mutagen. The results revealed a significantly higher level of DNA damage at all concentrations of Cypermethrin tested compared to control and background level (p < 0.05). We have standardized the technique for one of the most common native fish species that will be useful for biomonitoring genotoxicity in polluted waters of the region.     

焦炉工尿中1-羟基芘水平与早期遗传学效应的关系

目的 研究焦炉工尿中1-羟基芘水平与外周血淋巴细胞胞质分裂阻滞微核和彗星尾矩间的关系。方法 分别选取133名焦炉作业工人和28名非职业暴露人员,使用碱水解-高效液相色谱法测定尿中1-羟基芘浓度作为个体多环芳烃暴露内剂量,分别应用彗星试验和胞质分裂阻滞微核法评价了研究对象外周血淋巴细胞DNA和染色体损伤,使用调查表收集职业暴露史、年龄、性别、吸烟和饮酒状况等信息。结果 调整了年龄、性别、吸烟和饮酒状况后,尿中1-羟基芘浓度与外周血淋巴细胞微核细胞率和彗星尾矩均存在良好的相关关系。进一步按尿中1-羟基芘水平将研究对象分成0．30～2．44(54人)、2．45～7．09(53人)和7．10～33．10μmol／mol肌酐组(54人)3个内剂量组,3组个体尿中1-羟基芘的几何均值分别为1．14、4．32和12．49μmol／mol肌酐。使用多元非参数协方差分析校正了不同内剂量组个体的年龄、性别、吸烟和饮酒状况后,7．10～33．10μmol／mol肌酐组的彗星尾矩(中位数3．67)显著性高于2．45～7．09和0．30～2．44μmol／mol肌酐组(中位数分别为1．68和1．12),但后2组之间差异无显著性;2．45～7．09和7．10～33．10μmol／mol肌酐组微核率的中位数分别为8．00‰和7．50‰,2组间的差异无显著性,但均显著高于0．30～2．44μmol／mol肌酐组的6．00‰。结论 外周血淋巴细胞的彗星尾矩较胞质分裂阻滞微核能更好地反映多环芳烃暴露导致的早期遗传学效应。     

PARP-1抑制剂4-氨基-1,8-萘二胺增加阿霉素对小鼠胚胎成纤维细胞敏感性的研究

目的研究抑制聚腺苷酸二磷酸核糖转移酶-1[PARP-1]活性能否增加阿霉素(ADM)的细胞敏感性。方法以小鼠胚胎成纤维细胞为研究对象,将细胞按是否经PARP-1抑制剂4-氨基-1,8-萘二胺(4-AN)处理分为处理组和对照组,比较两组细胞经ADM染毒后细胞存活情况和DNA单链断裂及染色体损伤的差异。结果 4-AN处理组细胞的阿霉素半数抑制浓度(1.09±0.15μg/ml)低于对照组(2.19±0.22μg/ml),差异有显著性(P=0.002);在0.025～0.2μg/ml时,群体倍增时间较对照组长(P<0.05),0.05～0.2μg/ml时,集落形成率较对照组低(P<0.05)。单细胞凝胶电泳及微核实验结果显示,当ADM浓度范围为0.02～0.5μg/ml时,4-AN处理组细胞的拖尾率、尾长、Olive尾矩3个指标值均大于对照组(P<0.05),在ADM为0.01～0.2μg/ml时,4-AN处理组细胞的微核细胞率和细胞微核率均比对照组高(P<0.05)。结论抑制PARP-1活性能显著增加阿霉素的细胞敏感性,其机制与DNA损伤修复有关。     

有机膨润土遗传毒性的体外试验研究

目的 体外试验研究有机膨润土的遗传毒性.方法 人B淋巴母细胞(HMy2.CIR)染毒0、1.88、3.75、7.50、15.00μg/ml有机膨润土24、48、72 h,并设硫酸钙(30μg/ml)和游离SiO2(30、240μg/ml)为阴性和阳性颗粒对照.用彗星试验和胞浆分裂阻滞微核试验(cytokinesis-block micronucleus,CBMN)检测有机膨润土颗粒部分和可溶性部分的遗传毒性.结果 彗星试验结果表明,有机膨润土组彗星尾部DNA百分含量(%tail DNA)随染毒剂量和时间的增加而增高,剂量为15.00 μg/ml、染毒时间24、48、72 h时的%tail DNA分别为3.20±0.19、4.63±0.88和9.49±1.31,均明显高于30μg/ml硫酸钙组(分别为1.40±0.11、1.37±0.22和0.90±0.16)和30μg/ml二氧化硅组(分别为1.83±0.21、1.41±0.27和2.48±0.25),差异均有统计学意义(P＜0.01).CBMN试验结果发现,有机膨润土组(除1.88μg/ml染毒24h外)微核率(MNF)均明显高于30μg/ml硫酸钙组(分别为1.33‰±0.58‰、1.33‰±1.15‰和1.33‰±0.58‰)和30μg/ml二氧化硅组的MNF(分别为2.00‰±0.00‰、1.68‰±0.58‰和2.33‰±0.58‰),差异有统计学意义(P＜0.01).2种试验结果还表明有机膨润土可溶性部分并不诱发遗传毒性.结论 体外试验有机膨润土可诱发人B淋巴细胞系DNA损伤和微核率增高,毒性主要来源于不可溶部分.     

用彗星实验和微核实验检测地面水污染的遗传毒性效应

目的探索应用彗星实验(单细胞凝胶电泳技术,SCGE)测定鲤鱼红细胞DNA损伤以评价地面水污染遗传毒性效应的可行性。方法应用单细胞凝胶电泳和微核实验对污染指数(PI)不同的5种河流中采集的鲤鱼的红细胞DNA损伤和微核率进行测定。结果5种地面水水源中的鲤鱼红细胞DNA损伤情况不全相同,与阴性对照组比较差异有显著性(P<0.05),与污染严重程度呈正相关,趋势与微核实验一致。结论SCGE测定鲤鱼红细胞DNA损伤,可以检测地面水的污染状况。     

Assessing the genotoxicity of imidacloprid and RH-5849 in human peripheral blood lymphocytes in vitro with comet assay and cytogenetic tests

A combined approach employing comet assay and micronucleus (MN) and sister chromatid exchanges (SCE) tests was utilized to assess the genotoxicity of two pesticides, imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] and RH-5849 [2'-benzoyl-1'-tert-butylbenzoylhydrazine], on human peripheral blood lymphocytes in vitro. No significant difference in the frequencies of MN and SCE from the negative groups (P>0.05) was observed at low dose levels (i.e., 0.05 mg/L for imidacloprid and 5mg/L for RH-5849). As the concentrations of imidacloprid and RH-5849 were increased to 0.1 and 25 mg/L, respectively, significant effects to the frequencies of MN and SCE (P<0.05) were achieved relative to those of the negative controls. MN and SCE frequencies increased similarly in a dose-related manner with both pesticides. With the comet assay, however, the distribution of DNA damage grades in all the pesticide-treated groups was significantly different from those in the control (P<0.01). DNA damage scores increased with the exposure levels of both pesticides, and linear dose-effect relationships were observed for both imidacloprid (r2=0.98) and RH-5849 (r2=0.92). The cytogenetic techniques and comet assay revealed potential adverse effects of both imidacloprid and RH-5849 in human peripheral blood lymphocytes in vitro. Combination of the comet assay and cytogenetic tests appears commendable to assess the potential risks of human exposure to the pesticides.     

氯化钕对小鼠骨髓细胞的遗传毒作用

[目的]探讨氯化钕对小鼠骨髓细胞遗传物质的影响。[方法]小鼠腹腔注射氯化钕染毒,采用微核测[试技术和单细胞凝胶电泳技术检测小鼠骨髓红细胞微核率和彗星细胞DNA拖尾率。微核试验设置20、40、80、160mg/kg4个剂量组,彗星试验设置20、40、80mg/kg3个剂量组。[结果]在20～160mg/kg剂量范围内,随着氯化钕剂量的增加小鼠骨髓细胞微核率（FMN）升高（rFMN=0.956）;在20～80mg/kg剂量范围内,彗星细胞DNA拖尾率（PTC）和尾长（TL）随着剂量的增加而增加,存在剂量-效应关系（rPTC=0.946,rTL=0.997）。[结论]氯化钕对小鼠骨髓细胞具有一定的遗传毒作用。     

甲醛和苯联合吸入致雄性小鼠骨髓细胞的遗传毒性

[目的]研究甲醛和苯联合吸入染毒对雄性小鼠骨髓细胞的遗传毒性作用。为评价甲醛和苯的安全性提供科学依据。[方法]60只健康清洁级昆明种纯系雄性小鼠,随机分为10组,每组6只。各组分别为阴性对照组（清洁空气）,甲醛低（1．0mg／m^3）、中（3．0mg／m^3）、高（5．0mg／m^3）剂量组;苯低（500．0mg／m^3）、中（1500．0mg／m^3）、高（2500．0mg／m^3）剂量组,联合染毒低（0．5mg／m^3甲醛＋250．0mg／m^3苯）、中（1．5mg／m^3甲醛＋750．0mg／m^3苯）、高（2．5mg／m^3甲醛＋1250．0mg／m^3苯）剂量组。采用静式吸入染毒,每天2h,连续14d。染毒结束次日处死小鼠,采用微核试验和单细胞凝胶电泳试验（彗星试验）检测甲醛和苯单独或联合染毒致骨髓细胞的遗传毒性。[结果]与阴性对照组相比,甲醛、苯单独及联合染毒各剂量组均呈现骨髓细胞微核率升高、彗星尾部DNA含量增多、尾距增大（P〈0．05）。与相应单独染毒组相比,联合染毒各剂量组骨髓细胞微核率明显升高（P〈0．05）;联合染毒低、中剂量组彗星尾部DNA含量增多、尾距增大（P〈0．05）;联合染毒高剂量组彗星尾部DNA含量和尾距高于甲醛高剂量染毒组（P〈0．05）,与苯高剂量染毒组比较,其差异无统计学意义。[结论]甲醛和苯联合吸入染毒对雄性小鼠骨髓细胞的遗传损伤作用大干甲醛、苯单独染毒时的作用,二者对雄性小鼠骨髓细胞的联合遗传毒性作用可能具有协同作用。     

氧化型染发剂遗传毒性的体内外微核试验

目的探讨体外或体内微核试验在氧化型染发剂遗传毒性评价中的应用。方法使用小鼠骨髓细胞微核试验及中国仓鼠肺细胞(CHL细胞)体外微核试验方法检测染发剂作用于小鼠骨髓细胞及CHL细胞后产生的微核率。结果 6种染发剂在体外微核试验中的微核率高于对照组,差异均有统计学意义(P0.05,P0.01),在体内微核试验中与对照组相比,差异均无统计学意义(P0.05)。结论体外或体内微核试验用于检测染发剂的遗传毒性出现不同结果,有必要进一步探讨遗传毒性的测试组合。     

Evaluation of genotoxic and/or co-genotoxic effects in cells exposed in vitro to extremely-low frequency electromagnetic fields

During the last two decades, concerns have arisen regarding a possible association between extremely-low frequency (ELF) electromagnetic fields (EMF) exposure and cancer incidence (e.g. childhood acute leukaemia, cancer of the nervous system, and lymphomas). In 1979, Wertheimer and Leeper firstly reported an excess of cancer mortality among children living in homes located near power lines and presumably exposed to elevated magnetic fields. Subsequently, a large number of epidemiological studies investigated the possible association between residential or occupational exposure to ELF-EMF and cancer. Several in vivo and in vitro models have been investigated with the effort to determine a link, if any, between such fields and mutagenesis and to determine the possible mechanism of cancer risk. However, a causal relationship between exposure to ELF-EMF and cancer has been suggested but has not been unequivocally demonstrated. In 1998, following an analysis of the results retrieved in the literature, the U.S. National Institute of Environmental Health Sciences proposed to apply a "possible human carcinogen" category (Group 2B) to ELF-EMF. More recently, in 2002, the same classification for ELF-MF was proposed by the International Agency for Research on Cancer. In this in vitro approach, to test the genotoxic and/or co-genotoxic potency of ELF-MF, we used the alkaline single-cell microgel-electrophoresis (comet) assay and the cytokinesis block micronucleus test. Co-exposure assays were performed in the presence of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroquinoline N-oxide (4NQO), benzene, 1,4-benzenediol (1,4-BD), or 1,2,4-benzenetriol (1,2,4-BT). An ELF-MF (50 Hz, 5 mT) was obtained by a system composed of capsulated induction coils. ELF-MF alone was unable to cause direct primary DNA damage. Whereas, an increased extent of DNA damage was observed in cells co-exposed to ELF-MF and MNNG, 1,4-BD, or 1,2,4-BT. An opposite trend was observed in cells treated with 4NQO and co-exposed to ELF-MF. Moreover, the frequency of micronucleated cells in ELF-MF-exposed cells was higher than in control cultures. Our findings suggest that the tested ELF-MF (50 Hz, 5 mT) possess genotoxic (micronucleus test) and co-genotoxic (comet assay) capabilities. The possibility that ELF-MF might interfere with the genotoxic activity of xenobiotics has important implications, since human populations are likely to be exposed to a variety of genotoxic agents concomitantly with exposure to this type of physical agent.