Mutat Res. 1988 Feb;204(2):307-16.
The Collaborative Study Group for the Micronucleus Test, a task group of the Environmental Mutagen Society of Japan, has earlier addressed the question of sex difference as a source of variation in the micronucleus test. Strain difference, another issue in test protocols requiring urgent clarification, was selected as the subject of the second study. Male mice of strains Slc:ddY (ddY), CRJ: CD-1(ICR) (CD-1), Slc:BDF1 (BDF1), and ms:Hal (ms) were treated with 6 different chemicals chosen from various classes of micronucleus inducers: colchicine, 7,12-dimethylbenz[a]anthracene, ethyl methanesulfonate, N-ethyl-N-nitrosourea, 6-mercaptopurine, and potassium chromate. All 4 strains gave positive results with all 6 chemicals, although ms tended to show the highest responses. ddY and CD-1 were low responders, while BDF1 was intermediate between ms and the other two. Although ms seemed superior to the other strains, its high responses became manifest mostly at high dose levels. ms was not always the most sensitive strain; it responded moderately to ethyl methanesulfonate. Also the background level of micronucleated polychromatic erythrocytes was the highest in ms, but this did not explain the apparent high sensitivity of this strain. Despite the strain differences, it can be concluded that any of the other strains used seems to suffice as a tester for the micronucleus test.
微核试验协作研究组是日本环境诱变剂学会的一个特别工作组，此前已探讨了性别差异这一微核试验中变异来源的问题。试验方案中另一个亟待明确的问题——品系差异，被选为第二项研究的主题。选用了Slc:ddY（ddY）、CRJ:CD-1(ICR)（CD-1）、Slc:BDF1（BDF1）和ms:Hal（ms）这几个品系的雄性小鼠，用从各类微核诱导剂中选出的6种不同化学物质进行处理：秋水仙碱、7,12-二甲基苯并[a]蒽、甲磺酸乙酯、N-乙基-N-亚硝基脲、6-巯基嘌呤和铬酸钾。所有4个品系对所有6种化学物质均给出阳性结果，不过ms品系往往呈现出最高的反应。ddY和CD-1是低反应者，而BDF1的反应介于ms与其他两个品系之间。尽管ms品系似乎优于其他品系，但其高反应大多在高剂量水平时才明显。ms并不总是最敏感的品系；它对甲磺酸乙酯的反应适中。此外，ms品系中微核多染红细胞的背景水平也是最高的，但这并不能解释该品系明显的高敏感性。尽管存在品系差异，但可以得出结论，所使用的其他任何品系似乎都足以作为微核试验的受试品系。
