An in vitro micronucleus assay with size-classified micronucleus counting to discriminate aneugens from clastogens
| Autor: | Yumi Nakajima, Shigeo Matsumura, Kiyohiro Hashimoto, Fumio Chatani |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Cell Count
CHO Cells Toxicology Chinese hamster Clastogen chemistry.chemical_compound Cricetulus Cricetinae medicine Animals Metaphase Cell Nucleus Micronucleus Tests biology medicine.diagnostic_test Colcemid Mitomycin C General Medicine Telomere Aneugens Aneuploidy Flow Cytometry biology.organism_classification Molecular biology chemistry Micronucleus test Aneugen Micronucleus Mutagens Fluorescence in situ hybridization |
| Zdroj: | Toxicology in Vitro. 24:208-216 |
| ISSN: | 0887-2333 |
| DOI: | 10.1016/j.tiv.2009.09.006 |
| Popis: | In the in vitro micronucleus (MN) assay, genotoxic chemicals can be characterized as aneugens and clastogens by the presence and absence of kinetochore protein or centromere regions in the micronuclei, respectively. Aneugens preferentially induce kinetochore- or centromere-positive micronuclei which can be detected by the immunofluorescence staining method or the fluorescence in situ hybridization (FISH) method. Both methods are robust and reliable; however, these assays require a definite period of time and cost to obtain a result that suggests that the genotoxic chemicals cause aneuploidy. This is why these methods are not adequate to evaluate dozens of chemicals which are mixtures of aneugens and clastogens. To evaluate a batch of chemicals, a quicker and more convenient assay is desirable. In the present study, we examined whether the size-classified counting of MN is as effective as the FISH method to characterize aneuploidy in the in vitro MN assay using Chinese hamster lung (CHL) cell lines. As aneugens, 9 substances (colcemid, vincristine sulfate, paclitaxel, thiabendazole, diethylstilbestrol, griseofulvin, bisphenol A, fisetin and okadaic acid) were used; as clastogens 6 substances (methylmethane sulfonate, N-methyl-N'-nitro-N-nitroso-guanidine, etoposide, mitomycin C, hydroxyurea and actinomycin D) were used. The size-classified counting revealed that all the 9 aneugens increased both the frequency and proportion of large-size MN as compared with the vehicle control. Although N-methyl-N'-nitro-N-nitroso-guanidine, etoposide and mitomycin C increased the frequency, no increase was observed in the proportion. Meanwhile, with the FISH method, all the aneugens induced centromere-positive micronuclei but the clastogens did not. Based on these results, it is considered that the frequency of large-size MN in the in vitro MN assay is an alerting index for aneugenic effects and that its proportion is a simple and reliable index which is as effective as the FISH analysis for discrimination of aneugens from clastogens. |
| Databáze: | OpenAIRE |
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