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目的利用微核试验了解松木刨花和枫木刨花的遗传毒性。方法80只NIH种小白鼠随机分为8组,每组10只。其中3组分别以100、50、12.5g/kg剂量的松木刨花水提取物染毒,另3组分别以100、50、12.5g/kg剂量的枫木刨花水提取物染毒,1组(阳性对照组)以环磷酰胺50mg/kg染毒,1组((阴性对照组)以生理盐水染毒。染毒方法均是先经口染毒,24h后以同样剂量再次灌胃。6h后颈椎脱臼处死动物,制片,观察并计数嗜多染红细胞的微核率。结果以松木刨花及枫木刨花水提取物染毒的各组小白鼠的微核率与阳性对照组比较差异有统计学意义(P<0.01),与阴性对照组比较差异无统计学意义(P>0.05)。结论松木刨花和枫木刨花的水提取物对小鼠的骨髓细胞未见有何致突变性。 相似文献
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Arsenic (As), one of the most harmful toxicant at the global level, severely affects plant metabolism when taken up. Interestingly, the presence of silicon (Si) as a fertilizer in As-contaminated soil is an effective strategy to decrease As accumulation in plants. Brassica juncea (var. Varuna) were grown hydroponically to investigate the role of Si at biochemical and molecular levels under arsenite (As3+) stress. Seedlings of B. juncea were exposed to As3+, Si, and a combination of both elements. Our data demonstrated that seedlings exposed to As3+ showed an inhibition in shoot length, chlorophyll, carotenoid, and protein, while co-application of Si improved these growth parameters. Silicon supplementation reduced As accumulation in shoot. Increase/decrease was observed in stress-related parameters (cysteine and proline), antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, and catalase), and oxidative stress markers (malondialdehyde and H2O2), which were improved upon co-application of Si as compared to As3+ alone treatment. Random amplified polymorphic DNA (RAPD) is a suitable biomarker assay for plants for assessing the genotoxicity. Seven RAPD primers produced a total of 39 and 48 bands in the leaves of the untreated and treated seedlings, respectively. The RAPD band-profiles and genomic template stability were consistent with other growth and physiological parameters. In conclusion, the genotoxic alterations along with the biochemical parameters indicate that the exposure to Si mitigates As3+-induced oxidative stress by improving the stress-related parameters and antioxidant system in B. juncea. 相似文献
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研究了混合重金属对鲫鱼Na/K ATPase活性及DNA合成作用的影响,结果表明:鱼鳃、鱼脑和肝脏的Na/K ATPase活性与混合重金属的浓度呈显著的负线性相关关系;3种组织Na/K ATPase活性的敏感顺序为鱼脑>鱼鳃>肝脏.且抑制这3种组织Na/K ATPase活性50%的浓度分别为1.63mg/kg,0.92 mg/kg和2.02 mg/L.DNA掺入试验表明:注射3H-TdR后取样的最佳时间为6 h;混合重金属对鱼体各组织DNA合成作用呈现双向效应,即低浓度时,3H-TdR掺入量增大,表现出损伤、修复作用,高浓度时,3H-TdR的掺入量显著低于对照,组织细胞DNA的合成受到了抑制作用;鱼鳃和肝脏的Na/K ATPase活性与掺入组织DNA中3H-TdR的放射性有显著的相关性. 相似文献
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Thomas?Kosmehl Falk?Krebs Werner?Manz Lothar?Erdinger Thomas?Braunbeck Henner?HollertEmail author 《Journal of Soils and Sediments》2004,4(2):84-94
Goals, Scope and Background
Improved quality of surface waters and sediments requires advanced strategies for ecotoxicological assessment. Whilst at least in Germany assessment strategies on the basis of chemical analysis and acute toxicity data dominated the last decades, the development of more specific biological endpoints and biomarkers in ecotoxicology is required in order to arrive at a good ecological potential and good chemical status of surface waters in the European river basins until the year 2015, as required by the European Water Framework Directive. Since sediments have for long been known to function both as a sink and as a source of pollutants in aquatic systems, and since part of the particle-associated substances have frequently been demonstrated to cause mutagenic and carcinogenic effects in aquatic organisms, particularly in fish, there is, among other requirements, an urgent need to develop, standardize and implement integrated vertebrate-based test systems addressing genotoxicity into recent sediment investigation strategies. Thus, the present study was designed to compare the suitability of two commonly used test systems, the comet assay and the Ames test, for the evaluation of the ecotoxicological burden of surface and core sediment samples from the river Rhine.Methods (or Main Features)
In order to determine the importance of inherent enzymatic activities, two permanent fish cell lines with different biotransformation capacities, RTL-W1 and RTG-2, were compared with respect to their capability of detecting genotoxic effects in 18 surface and core sediment samples from 9 locations along the River Rhine in the comet assay with and without exogenous bioactivation. For further comparison, as a prokaryotic mutagenicity assay, theSalmonella plate incorporation assay (Ames test) with the test strains TA98 and TA 100 with and without exogenous metabolic activation was used.Results and Discussion
Whereas all sediment extracts induced genotoxic effects in the comet assay with RTL-W1 cells, only 12 out of 18 sediment extracts revealed significant genotoxicity in the tests with the less biotransformation-competent RTG-2 cells. Exogenous bioactivation by addition of ß-naphthoflavone /phenobarbital-induced S9 from rat liver resulted in both reduction or increase of genotoxicity in samples from different sites, however, without consistent reaction patterns. In general, the responses of RTL-W1 cells indicated higher biotransformation capacity than in RTG-2 cells without S9 complementation. In Ames tests using TA98 with S9, 16 out of 18 extracts induced significant mutagenicity with induction factors up to 4. Compared to TA98, the strain TA100 proved less sensitive, with maximum induction factors of 1.3, indicating the potential presence of substances inducing frarneshift mutations, which can only be detected in the strain TA98. Chemical analyses revealed particularly high levels of hexachlorbenzene (up to 860 µg/kg) and priority PAHs (up to 4.8 mg/kg); so far, however, no correlation could be found between compounds analyzed and the corresponding biotests.Conclusions
Results document that both comet assay and Ames test are capable of detecting xenobiotic interaction with DNA in consequence of exposure to complex environmental samples. Whereas the alkaline version of the comet assay detects a broad range of interactions with the DNA, however without information about their eventual importance, the Ames test only reveals established mutations, but fails to detect transient (reparable) DNA alterations. However, even transient primary changes in the DNA structure might result in carcinogenic processes and, eventually, in implications at the population level. As a consequence, for hazard assessment purposes, a combination of both assays is required to avoid false negatives in genotoxicity evaluation. Poor correlation between data obtained by chemical analysis and results in bioassays is indicative of our limited understanding of the sources of genotoxicity. In fact, numerous studies combining chemical and biological approaches for hazard assessment of complex environmental mixtures indicate that priority pollutant concentrations are a poor indicator of toxicity.If compared to the cell line RTG-2, RTL-W1 proved more effective in detecting genotoxicity in surface sediment samples and, thus, indicated the importance of bioactivation of at least part of the compounds in superficial layers of sediments. Results further document that the common assumption may be wrong that, in comparison to deeper strata, surface layers carry a lower toxic burden in consequence of the current decrease in water pollution. This might at least in part be due to remobilization of more heavily polluted sediments from deeper layers during severe flood events followed by re-sedimentation in flood plains or upstream weirs, where they might cover less polluted younger sediment layers.Recommendations and Perspectives
For a comprehensive assessment of genotoxicity in surface and core sediments, a combination of eukaryotic (comet assay) and prokaryotic assays (Ames test) with and without exogenous bioactivation is recommended. Since studies with organic sediments extracts simulate a worst-case scenario and fail to take into account bioavailability, there is broad consensus that whole-sediment exposure protocols represent the most realistic scenarios. Whereas more realistic solid phase exposure has frequently been applied in both microbial and invertebrate acute toxicity testing, there is an urgent need to develop corresponding whole sediment fish-based genotoxicity tests.6.
Kohei Matsushita Aki Kijima Yuji Ishii Shinji Takasu Meilan Jin Ken Kuroda Hiroaki Kawaguchi Noriaki Miyoshi Takehiko Nohmi Kumiko Ogawa Takashi Umemura 《Journal of toxicologic pathology》2013,26(1):19-27
In this study, the potential for development of an animal model (GPG46) capable of rapidly detecting chemical carcinogenicity and the underlying mechanisms of action were examined in gpt delta rats using a reporter gene assay to detect mutations and a medium-term rat liver bioassay to detect tumor promotion. The tentative protocol for the GPG46 model was developed based on the results of dose-response exposure to diethylnitrosamine (DEN) and treatment with phenobarbital over time following DEN administration. Briefly, gpt delta rats were exposed to various chemicals for 4 weeks, followed by a partial hepatectomy (PH) to collect samples for an in vivo mutation assay. The mutant frequencies (MFs) of the reporter genes were examined as an indication of tumor initiation. A single intraperitoneal (ip) injection of 10 mg/kg DEN was administered to rats 18 h after the PH to initiate hepatocytes. Tumor-promoting activity was evaluated based on the development of glutathione S-transferase placental form (GST-P)-positive foci at week 10. The genotoxic carcinogens 2-acetylaminofluorene (2-AAF), 2-amino-3-methylimidazo [4,5-f] quinolone (IQ) and safrole (SF), the non-genotoxic carcinogens piperonyl butoxide (PBO) and phenytoin (PHE), the non-carcinogen acetaminophen (APAP) and the genotoxic non-hepatocarcinogen aristolochic acid (AA) were tested to validate the GPG46 model. The validation results indicate that the GPG46 model could be a powerful tool in understanding chemical carcinogenesis and provide valuable information regarding human risk hazards. 相似文献
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不同工业污水对蚕豆根尖微核细胞率的影响 总被引:2,自引:1,他引:1
为了解不同工业污水对环境造成的污染程度,以蚕豆根尖细胞为试验材料,利用蚕豆根尖微核技术,对重庆市4种类型工业污水对蚕豆根尖细胞的遗传毒性进行微核测定试验.结果表明:农药厂、化工厂(2个)、电池厂、油漆厂等污水诱发的微核细胞率分别为(22.33±0.88)‰、(30.67±0.88)‰、(39.67±1.76)‰、(33.33±1.76)‰、(25.00±1.16)‰,与阴性对照组相比,差异极显著(P<0.01).结论是不同类型的工业污水对蚕豆根尖细胞微核的影响有差异,其中,化工厂和电池厂的污水诱导的蚕豆根尖细胞微核率最高,而农药厂和油漆厂污水诱导的蚕豆根尖细胞微核率较低. 相似文献
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Ettlin RA Kuroda J Plassmann S Hayashi M Prentice DE 《Journal of toxicologic pathology》2010,23(4):213-234
To illustrate the process of addressing adverse preclinical findings (APFs) as outlined in the first part of this review, a number of cases with unexpected APF in toxicity studies with drug candidates is discussed in this second part. The emphasis is on risk characterization, especially regarding the mode of action (MoA), and risk evaluation regarding relevance for man. While severe APFs such as retinal toxicity may turn out to be of little human relevance, minor findings particularly in early toxicity studies, such as vasculitis, may later pose a real problem. Rodents are imperfect models for endocrine APFs, non-rodents for human cardiac effects. Liver and kidney toxicities are frequent, but they can often be monitored in man and do not necessarily result in early termination of drug candidates. Novel findings such as the unusual lesions in the gastrointestinal tract and the bones presented in this review can be difficult to explain. It will be shown that well known issues such as phospholipidosis and carcinogenicity by agonists of peroxisome proliferator-activated receptors (PPAR) need to be evaluated on a case-by-case basis. The latter is of particular interest because the new PPAR α and dual α/γ agonists resulted in a change of the safety paradigm established with the older PPAR α agonists. General toxicologists and pathologists need some understanding of the principles of genotoxicity and reproductive toxicity testing. Both types of preclinical toxicities are major APF and clinical monitoring is difficult, generally leading to permanent use restrictions. 相似文献
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Kerstin Hund-Rinke Werner Kördel Dieter Hennecke Adolf Eisenträger Stefanie Heiden 《Journal of Soils and Sediments》2002,2(1):43-50
For the assessment of contaminated or remediated soils, in addition to chemical analyses, ecotoxicological tests are performed which focus on the retention function of soils (determined by tests with aqueous soil extracts) and on the habitat function (determined by tests with soil). While numerous standardized test guidelines exist to investigate effects by chemical substances, respective test procedures for soil assessments are lacking. To close this gap, a round robin test was performed to support standardization. Four contaminated soils were tested using a total of fifteen test systems including ecotoxicological and genotoxicological tests with soil extracts and soil. The results obtained from the tests with soil extracts are presented in this article. 相似文献