Micronucleus test using formalin-fixed rat glandular stomach and colon
Abstract Background Genotoxicity in tissues other than hematopoietic tissues, such as the liver and gastrointestinal (GI) tract, is an important focus in the risk assessment of chemicals in humans. We previously developed a rat micronucleus test for the GI tract, which is the first contact tissue wh...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2023-01-01
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| Series: | Genes and Environment |
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| Online Access: | https://doi.org/10.1186/s41021-023-00259-4 |
| _version_ | 1797952345847365632 |
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| author | Wakako Ohyama Yohei Fujiishi Emiko Okada Kazunori Narumi Makoto Hayashi |
| author_facet | Wakako Ohyama Yohei Fujiishi Emiko Okada Kazunori Narumi Makoto Hayashi |
| author_sort | Wakako Ohyama |
| collection | DOAJ |
| description | Abstract Background Genotoxicity in tissues other than hematopoietic tissues, such as the liver and gastrointestinal (GI) tract, is an important focus in the risk assessment of chemicals in humans. We previously developed a rat micronucleus test for the GI tract, which is the first contact tissue where chemicals are introduced into the body through oral exposure. Target cells were obtained from fresh tissue samples by ethylenediaminetetraacetic acid disodium salt (EDTA) treatment. As an improvement to this method, we have used formalin-fixed tissues instead of fresh tissues; this approach can be used for tissues that are sampled from other toxicological tests and that are archived for several years. This new method can be used for examining micronucleus induction retrospectively when needed. In the present study, we compared the performance of the EDTA method and the new method with formalin-fixed tissues (formalin-fixation method). Results Histological examination showed that both the EDTA and formalin-fixation methods could be used for collecting cells located in or above the proliferative zone of the GI tract tissues of rats. In addition, the collected cells were similar in shape. We conducted micronucleus tests with rat GI tract tissues by the two methods using model chemicals, which were used as positive control chemicals (a combination of diethylnitrosamine, 1,2-dimethylhydrazine dihydrochloride, and potassium bromate). The two methods showed similar results. We additionally evaluated the aging effect of tissues stored in formalin fixative. The results showed that 1 year of storage did not affect the frequency of micronucleated cells. Conclusion The equivalence of the EDTA and formalin-fixation methods was confirmed, and micronucleus analysis was possible up to at least 1 year after formalin fixation of the GI tract, indicating that the formalin-fixation method is valuable for the rat GI tract micronucleus test. |
| first_indexed | 2024-04-10T22:44:51Z |
| format | Article |
| id | doaj.art-6724dffd54d54af29c02fd8039a2f6a2 |
| institution | Directory Open Access Journal |
| issn | 1880-7062 |
| language | English |
| last_indexed | 2024-04-10T22:44:51Z |
| publishDate | 2023-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Genes and Environment |
| spelling | doaj.art-6724dffd54d54af29c02fd8039a2f6a22023-01-15T12:21:40ZengBMCGenes and Environment1880-70622023-01-014511710.1186/s41021-023-00259-4Micronucleus test using formalin-fixed rat glandular stomach and colonWakako Ohyama0Yohei Fujiishi1Emiko Okada2Kazunori Narumi3Makoto Hayashi4Yakult Central Institute, Yakult Honsha Co., Ltd.Yakult Central Institute, Yakult Honsha Co., Ltd.Yakult Central Institute, Yakult Honsha Co., Ltd.Yakult Central Institute, Yakult Honsha Co., Ltd.makoto international consultingAbstract Background Genotoxicity in tissues other than hematopoietic tissues, such as the liver and gastrointestinal (GI) tract, is an important focus in the risk assessment of chemicals in humans. We previously developed a rat micronucleus test for the GI tract, which is the first contact tissue where chemicals are introduced into the body through oral exposure. Target cells were obtained from fresh tissue samples by ethylenediaminetetraacetic acid disodium salt (EDTA) treatment. As an improvement to this method, we have used formalin-fixed tissues instead of fresh tissues; this approach can be used for tissues that are sampled from other toxicological tests and that are archived for several years. This new method can be used for examining micronucleus induction retrospectively when needed. In the present study, we compared the performance of the EDTA method and the new method with formalin-fixed tissues (formalin-fixation method). Results Histological examination showed that both the EDTA and formalin-fixation methods could be used for collecting cells located in or above the proliferative zone of the GI tract tissues of rats. In addition, the collected cells were similar in shape. We conducted micronucleus tests with rat GI tract tissues by the two methods using model chemicals, which were used as positive control chemicals (a combination of diethylnitrosamine, 1,2-dimethylhydrazine dihydrochloride, and potassium bromate). The two methods showed similar results. We additionally evaluated the aging effect of tissues stored in formalin fixative. The results showed that 1 year of storage did not affect the frequency of micronucleated cells. Conclusion The equivalence of the EDTA and formalin-fixation methods was confirmed, and micronucleus analysis was possible up to at least 1 year after formalin fixation of the GI tract, indicating that the formalin-fixation method is valuable for the rat GI tract micronucleus test.https://doi.org/10.1186/s41021-023-00259-4Micronucleus testGastrointestinal tractGlandular stomachColonFormalin-fixation method |
| spellingShingle | Wakako Ohyama Yohei Fujiishi Emiko Okada Kazunori Narumi Makoto Hayashi Micronucleus test using formalin-fixed rat glandular stomach and colon Genes and Environment Micronucleus test Gastrointestinal tract Glandular stomach Colon Formalin-fixation method |
| title | Micronucleus test using formalin-fixed rat glandular stomach and colon |
| title_full | Micronucleus test using formalin-fixed rat glandular stomach and colon |
| title_fullStr | Micronucleus test using formalin-fixed rat glandular stomach and colon |
| title_full_unstemmed | Micronucleus test using formalin-fixed rat glandular stomach and colon |
| title_short | Micronucleus test using formalin-fixed rat glandular stomach and colon |
| title_sort | micronucleus test using formalin fixed rat glandular stomach and colon |
| topic | Micronucleus test Gastrointestinal tract Glandular stomach Colon Formalin-fixation method |
| url | https://doi.org/10.1186/s41021-023-00259-4 |
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