Population doubling: A simple and more accurate estimation of cell growth suppression in the in vitro assay for chromosomal aberrations that reduces irrelevant positive results
Population doubling: A simple and more accurate estimation of cell growth suppression in the in vitro assay for chromosomal aberrations that reduces irrelevant positive results
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DOI：
10.1002/em.10207
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发表时间：
2004-01-01
影响因子：
2.8
通讯作者：
Galloway, SM
中科院分区：
文献类型：
--
作者：
Greenwood, SK;Hill, RB;Galloway, SM
体外染色体畸变测定的细胞毒性限值国际指南要求细胞生长减少超过 50%。这对毒性没有设定上限，并且人们担心畸变测定中获得的错误或不相关结果的数量，即仅在毒性剂量水平下出现阳性结果，没有主要 DNA 损伤能力的证据，并且在其他遗传毒性测试中出现阴性结果。我们之前提出，如果最高剂量的毒性不超过 50%，则不会漏掉真正的基因毒性化合物。通过细胞计数占对照的百分比来测量细胞生长可能会低估毒性。例如，如果我们在每个培养物中接种 50 万个细胞，而对照则加倍至对照的 150%。群体倍增 (PD) 的测量可以更准确地评估细胞生长。为了评估PD在剂量选择中的使用，我们检查了该实验室之前的数据以及来自“真实的”主要DNA损伤性断裂剂和断裂剂（包括药物）的新实验的数据，这些断裂剂被认为通过细胞毒性相关机制间接起作用。我们比较了畸变结果，其中最高剂量评分基于最终细胞计数减少 50%，而最高剂量基于 PD 时获得的结果。 PD 方法可以检测真正的断裂剂，包括那些在一定范围内具有一定毒性的活性断裂剂，并减少与毒性相关的“假”阳性结果的数量。 (C) 2004 Wiley Liss, Inc. 百万实验期间，真正没有生长的培养物仍然会有细胞计数
International guidelines for cytotoxicity limits for the in vitro chromosomal aberration assay require reductions in cell growth of greater than 50%. This sets no upper limit on toxicity and there is concern about the number of false or irrelevant results obtained in the aberration assay, i.e., positive results at toxic dose levels only, with no evidence for primary DNA damaging ability and with negative results in the other genotoxicity tests. We have previously proposed that no truly genotoxic compound would be missed if the toxicity of the highest dose did not exceed 50%. Cell growth measured by cell counts as a percentage of controls can underestimate toxicity. For example, if we seed half a million cells per culture, and the controls double to 150% of the control. Measurement of population doublings (PDs) more accurately assesses cell growth. To assess the use of PD in dose selection, we examined previous data from this lab and data from new experiments with "true," primary DNA damaging clastogens, and with clastogens, including drugs, thought to act indirectly, through cytotoxicity-associated mechanisms. We compared aberration results where the highest doses scored were based on 50% reductions in final cell counts with results obtained when the highest doses were based on PD. The PD method allows detection of true clastogens, including those that are active in a range with some toxicity, and reduces the number of toxicity-related "false"-positive results. (C) 2004 Wiley Liss, Inc. million during the experiment, a culture that truly has no growth will still have a cell count