title: Validation study of the in vitro micronucleus test in a Chinese hamster lung cell line (CHL/IU).
abstract: We conducted a collaborative validation study, under the auspices of the Japanese Ministry of Labour, on the in vitro micronucleus test to see if it could be used as an alternative to the in vitro chromosome aberration test for evaluation of chemical safety. We used the Chinese hamster lung cell line (CHL/IU), which is the most widely used system for the latter test in Japan, and evaluated 66 chemicals, including clastogens and polyploidy inducers. The cytochalasin B cytokinesis blocking method, which is commonly used in human lymphocyte culture, was applied to the established cell line, but did not improve the detection of chemically-induced micronuclei in continuously growing cells. The highest micronucleus frequencies were obtained at 48 or 72 h continuous treatments. In short treatments (6 h), a 42 h recovery time yielded the best responses. Concordance between the results of the micronucleus test and the chromosomal aberration test was satisfactorily high (88.7%), and we concluded that the in vitro micronucleus test could be used in place of the chromosomal aberration test as a simple and rapid method for detecting clastogens and aneugens in vitro. We also propose a protocol for the test.
authors.affiliation: Japan Bioassay Research Center, 2445 Hirasawa, Hadano-shi, Kanagawa 257-0015.
authors.forename: T
authors.initials: T
authors.lastname: Matsushima
authors.forename: M
authors.initials: M
authors.lastname: Hayashi
authors.forename: A
authors.initials: A
authors.lastname: Matsuoka
authors.forename: M
authors.initials: M
authors.lastname: Ishidate
authors.forename: K F
authors.initials: KF
authors.lastname: Miura
authors.forename: H
authors.initials: H
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Morimoto
authors.forename: H
authors.initials: H
authors.lastname: Ogura
authors.forename: K
authors.initials: K
authors.lastname: Mure
authors.forename: K
authors.initials: K
authors.lastname: Koshi
authors.forename: T
authors.initials: T
authors.lastname: Sofuni
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D002875:Chromosomes / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D003571:Cytochalasin B / Q000494:pharmacology; D005069:Evaluation Studies as Topic; D008099:Liver / Q000737:chemistry; D008168:Lung / Q000166:cytology; D008214:Lymphocytes / Q000187:drug effects; D015162:Micronucleus Tests / Q000379:methods* / Q000592:standards; D009153:Mutagens / Q000633:toxicity; D011123:Polyploidy; D051381:Rats
chemical_list: D009153:Mutagens; D003571:Cytochalasin B