彗星试验检测7种化合物对外周血淋巴细胞DNA的损伤

目的：检测过氧化氢（Ｈ２Ｏ２）、甲磺酸乙酯（ＥＭＳ）、丝裂霉素Ｃ（ＭＭＣ）、二甲基亚硝胺（ＤＭＮＡ）、苯并（ａ）芘（ＢａＰ）、２－氨基Ｗｕ（２－ＡＦ）和环磷酰胺（ＣＰ）诱发小鼠、大鼠及人外周血淋巴细胞ＤＮＡ单链断裂。方法：体外单细胞微量凝胶碱性电泳试验（慧星试验）。结果：除ＥＭＳ０．９７ｍｍｏｌ·Ｌ＾－１在小鼠淋巴细胞，ＭＭＣ３０μｍｏｌ·Ｌ＾－１在小鼠、人淋巴细胞中呈阴性外，其余均为阳性。最低可     

Comparative study of the comet assay and the micronucleus test in amphibian larvae (Xenopus laevis) using benzo(a)pyrene, ethyl methanesulfonate, and methyl methanesulfonate: establishment of a positive control in the amphibian comet assay

The present investigation explored the potential use of the comet assay (CA) as a genotoxicity test in the amphibian Xenopus laevis and compared it with the French standard micronucleus test (MNT). Benzo[a]pyrene (B[a]P), methyl methanesulfonate (MMS), and ethyl methanesulfonate (EMS) were used as model compounds for assessing DNA damage. Damage levels were measured as DNA strand breaks after alkaline electrophoresis of nuclei isolated from larval amphibian erythrocytes using the CA in order to establish a positive control for further ecotoxicological investigations. The results led to the selection of MMS as a positive control on the basis of the higher sensitivity of Xenopus laevis to this compound. The CA and MNT were compared for their ability to detect DNA damage with the doses of chemical agents and exposure times applied. EMS and MMS were shown to increase micronucleus and DNA strand break formation in larval erythrocytes concurrently. However, B[a]P increased micronucleus formation but not that of DNA strand breaks. Time-dose experiments over 12 days of exposure suggest that the CA provides an earlier significant response to genotoxicants than does the MNT. In Xenopus the CA appears to be a sensitive and suitable method for detecting genotoxicity like that caused by EMS and MMS. It can be considered a genotoxicity-screening tool. The results for B[a]P show that both tests should be used in a complementary manner on Xenopus.     

苯并(a)芘引起鼠胸腺细胞DNA损伤及其机制

目的研究苯并(a)芘引起的鼠胸腺细胞DNA损伤及其机制。方法在加或不加代谢活化系统(S9)条件下,运用单细胞凝胶电泳技术检测不同浓度苯并(a)芘所致的鼠胸腺细胞DNA损伤,同时观察抗氧化剂N-乙酰-L-半胱氨酸对其损伤的影响;采用比色法测定不同浓度苯并(a)芘染毒后鼠胸腺细胞NO含量。结果10-4、10-5和10-6mol/L苯并(a)芘( S9)染毒后,鼠胸腺细胞DNA迁移距离分别为(42.14±5.23)(、25.36±2.96)和(18.78±1.72)μm,与溶剂对照组(11.25±0.92)μm相比,差异有显著性,阳性组加入抗氧化剂N-乙酰-L-半胱氨酸后DNA迁移距离明显缩短;而鼠胸腺细胞NO含量并无显著增加。结论苯并(a)芘可引起鼠胸腺细胞DNA损伤,其损伤与苯并(a)芘代谢产生的活性氧有关,而NO可能不参其损伤。     

Evaluating the combinative effects on human lymphocyte DNA damage induced by ultraviolet ray C plus 1.8 GHz microwaves using comet assay in vitro

The objective of this study was to observe whether 1.8 GHz microwaves (MW) (SAR, 3 W/kg) exposure can influence human lymphocyte DNA damage induced by ultraviolet ray C (UVC). The lymphocytes, which were from three young healthy donors, were exposed to 254 nm UVC at the doses of 0.25, 0.5, 0.75, 1.0, 1.5 and 2.0 J m(-2), respectively. The lymphocytes were irradiated by 1.8 GHz MW (SAR, 3 W/kg) for 0, 1.5 and 4 h. The combinative exposure of UVC plus MW was conducted. The treated cells were incubated for 0, 1.5 and 4 h. Finally, comet assay was used to measure DNA damage of above treated lymphocytes. The results indicated that the difference of DNA damage induced between MW group and control group was not significant (P>0.05). The MTLs induced by UVC were 1.71+/-0.09, 2.02+/-0.08, 2.27+/-0.17, 2.27+/-0.06, 2.25+/-0.12, 2.24+/-0.11 microm, respectively, which were significantly higher than that (0.96+/-0.05 microm) of control (P<0.01). MTLs of some sub-groups in combinative exposure groups at 1.5-h incubation were significantly lower that those of corresponding UVC sub-groups (P<0.01 or P<0.05). However, MTLs of some sub-groups in combinative exposure groups at 4-h incubation were significantly higher that those of corresponding UVC sub-groups (P<0.01 or P<0.05). In this experiment it was found that 1.8 GHz (SAR, 3 W/kg) MW exposure for 1.5 and 4 h did not enhance significantly human lymphocyte DNA damage, but could reduce and increase DNA damage of human lymphocytes induced by UVC at 1.5-h and 4-h incubation, respectively.     

彗星试验检测石棉对V79细胞DNA损伤的研究

目的 研究石棉悬液和浸泡过滤上清液对V79细胞的DNA损伤情况，以进一步探讨石棉致癌机制。方法 用彗星试验检测3种石棉悬液和浸泡过滤上清液对V79细胞的DNA损伤情况。同时设立阴性对照组。结果 石棉悬液各剂量组细胞DNA的迁移距离与阴性对照组比较，差异均有显著性（P＜0．05或P＜0．01），且均有确切的剂量反应关系。结论 不仅石棉纤维对V79细胞DNA有物理损伤作用，而且其浸泡过滤上清液对V79细胞DNA有化学损伤作用。     

DNA damage caused by benzo(a)pyrene in MCF-7 cells is increased by verapamil, probenecid and PSC833

The aim of this study was to clarify whether pharmaceutical drugs capable of inhibiting ABC-transporters affect the toxicity of benzo(a)pyrene (BP). MCF-7 breast adenocarcinoma cells were cultured for 24 and 48 h with benzo(a)pyrene (1 microM) and the transporter inhibitors verapamil (0.125-100 microM), PSC833 (0.05-5 microM) or probenecid (0.05-2 mM). DNA binding of benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE) was analyzed by synchronous fluorescence spectrophotometry and p53 protein by immunoblotting. BP metabolism was studied using thin layer chromatography (TLC). MTT assay and ATP quantitation were used for the analysis of cell viability. At 24 h there was no statistically significant increase in the DNA-adduct formation by any of the used inhibitors. However, at 48 h all of the inhibitors, in concentrations known to effectively block ABC transporters, increased the BPDE-DNA adduct formation 1.5 to 2-fold compared to adduct formation with BP only. PSC833 and verapamil also increased p53 protein expression at 48 h (p<0.05). Probenecid decreased glucuronidation of (3)H-BP metabolites. Other inhibitors did not decrease statistically significantly the overall formation of water-soluble metabolites. BP alone slightly decreased viability of cells at 48 h according to ATP quantitation as compared to vehicle treated controls (86.4+/-16.4%). Even though the used inhibitors showed some cytotoxicity, the combination of BP and inhibitors did not decrease cell viability in synergistic manner. According to these results certain pharmaceutical drugs may increase DNA damage caused by benzo(a)pyrene in MCF-7 cells at least partly through the inhibition of transporters. Taking into account the complex metabolism of BP and lack of specificity of the inhibitors used, it is likely that increased DNA damage seen in this study was the result of multiple interactions between the inhibitors, BP metabolism and the efflux of the compounds.     

Detection of benzo(a)pyrene and mutagenicity in water of Lake Baikal (Russia) and rivers in Okayama (Japan) using the blue rayon method: A simplified handling and transportation of samples from remote sites

Blue rayon, an adsorbent selective to compounds having three or more fused rings, for detecting benzo(a)pyrene and measuring mutagenicity was used in Lake Baikal (Russia), Asahi River, Sasagase River, and Lake Kojima (Okayama, Japan). One gram of blue rayon was immersed in 1 L of water in a bottle, and manually shaken for 30 min. The blue rayon was recovered and transported to the laboratory where the analyses for benzo(a)pyrene and the mutagenicity assay were performed. The recovered benzo(a)pyrene from the water sample ranged from 0.13 to 0.65 ng/L for Lake Baikal and from 0.13 to 1.41 ng/L for the rivers and the lake in Okayama. Six samples out of 11 from Lake Baikal showed positive but weak mutagenicity. No mutagenicity was found in the samples from the rivers and the lake in Okayama. The present method allows easy sampling at remote sites because there is no need for transporting voluminous water samples to the place where analysis is performed. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 279–284, 1999     

单细胞凝胶电泳技术在甲基汞对小鼠胸腺淋巴细胞DNA损伤中的应用

目的 探讨甲基汞对小鼠胸淋巴细胞DNA损伤的作用。方法 采用单细胞凝胶电泳技术进行检测。结果 1／200－1／2LD。剂量组的甲基汞均可引起淋巴细胞DNA不同程度电泳迁移；A组（1／200LD50）、B组（1／20LD50）、C组（1／2LD50）DNA平均迁移长工与对照组之间差异有显著性（P＜0．05），并且C组与A、B两组之间差异也有显著性（P＜0．001）；B组尾直径／头直径、尾面积／总面积之比均与A组差异有显著性（P＜0．05）、C组各项之比均与A、B组差异有显著性（P＜0．05）。结论 甲基汞引起DNA链断裂损伤，随着甲基汞剂量的增加，淋巴细胞DNA损伤加重。     

Assessment of alteration of reproductive system in vivo induced by subchronic exposure to benzo(a)pyrene via oral administration

The objective of this study was to assess whether subchronic exposure to benzo(a)pyrene (BaP) via oral ingestion alter endpoints of the reproductive system of mice. Hsd: ICR (CD1) 10‐week‐old males (n = 8) were randomly assigned to the exposure group and control group. Mice were administered BaP for 30 and 60 days by daily gavage at doses of 1, 10, 50, and 100 mg/kg body weight per day. At the end of the experiments, mice were anesthetized and reproductive organs, including testes, seminal vesicles, prostate, and cauda epididymis, were removed and examined. Spermatozoa quality and DNA strand breaks were assessed—1 and 10 mg/kg/day of BaP for 30 and 60 days did not significantly induce altered morphology or weights of testes, prostate, seminal vesicle, and epididymis, and spermatozoa quality of mice; 100 mg/kg/day of BaP for 60 days decreased weights of testes, seminal vesicle, and cauda epididymis. BaP exposure also significantly decreased motility, normal head morphology, vitality, and concentration of mature spermatozoa. In addition, BaP exposure induced a significant increase in DNA strand breaks. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 1–8, 2015.     

血红素氧化酶在软骨藻酸对细胞DNA损伤中的作用

目的　　研究血红素氧化酶 (hemeoxygenase ,HO)系统在软骨藻酸 (domoicacid ,DA)对H4细胞DNA损伤中的作用。方法　应用单细胞凝胶电泳法 (SCGE)分别测定 0、0 0 64、0 64和 6 4μmol/LDA单独及与HO系统的活性阻断剂ZnPP 9(10 - 5mol/L)联合作用于H4细胞 6、12、2 4和 48h后彗星拖尾细胞率及拖尾尾长。结果　彗星拖尾细胞率 :中剂量和高剂量组各时间点均比对照组高 ,差异有显著性 (P <0 0 5 )。中剂量 +阻断剂组各时间点均相应高于中剂量组 ,差异有显著性 (P <0 0 5 )。彗星拖尾尾长 :中剂量组 12、2 4和 48h比对照组长 ,2 4、48h比低剂量组长 ,差异均有显著性 (P<0 0 5 )。高剂量组各时间点均比对照组、低剂量组和中剂量组长 ,差异有显著性 (P <0 0 5 )。高剂量 +阻断剂组和中剂量 +阻断剂组 2 4、48h分别高于高剂量和中剂量组 ,差异有显著性 (P <0 0 5 )。尾长 时间作Regression分析 ,各剂量组r差异值均有显著性 (P <0 0 1)。结论　软骨藻酸能诱导H4细胞DNA损伤 ,HO系统对这种损伤有一定的保护作用。