Identifying germ cell mutagens using OECD test guideline 488 (transgenic rodent somatic and germ cell gene mutation assays) and integration with somatic cell testing
Identifying germ cell mutagens using OECD test guideline 488 (transgenic rodent somatic and germ cell gene mutation assays) and integration with somatic cell testing
复制标题
DOI：
10.1016/j.mrgentox.2018.05.021
复制
发表时间：
2018-08-01
影响因子：
1.9
通讯作者：
Douglas, George R.
中科院分区：
文献类型：
--
作者：
Marchetti, Francesco;Aardema, Marilyn J.;Douglas, George R.
经济合作与发展组织测试指南 488 (TG 488) 提供了使用转基因啮齿动物 (TGR) 模型评估生殖细胞和体细胞致突变性的建议。然而，在选择同时评估两种细胞类型致突变性的最佳方法方面存在重要的数据差距。与在生殖细胞推荐设计（即小鼠和大鼠的 28 + 49d 和 28 + 70d，分别）。为了解决这些数据差距，健康与环境科学研究所遗传毒理学技术委员会的生殖细胞工作组审查了男性生殖细胞中可用的 TGR 致突变性数据，并描述了不同采样时间的小管生殖细胞的暴露历史，以评估其对使用 TG 488 进行生殖细胞致突变性测试的影响。我们的分析表明，评估以下方面的突变频率：i) 28 + 3d 附睾尾部精子并不能提供有意义的致突变性数据； ii)、28+3d时的小管生殖细胞仅在结果呈阳性时提供可靠的致突变性数据； iii) 28 + 28d 时的肾小管生殖细胞在小鼠和大鼠中产生可靠的阳性和阴性结果。因此，28+28天方案可以提供一种同时评估同一动物体细胞组织和生殖细胞致突变性的方法。需要进一步的工作来支持除根据当前 TG 488 的缓慢增殖组织之外的组织的 28 + 28d 方案。最后，提供建议来指导生殖细胞致突变性数据的实验设计以供监管提交，以及提高 TGR 测定可靠性的其他可能方法。
The Organisation for Economic Co-operation and Development Test Guideline 488 (TG 488) provides recommendations for assessing germ cell and somatic cell mutagenicity using transgenic rodent (TGR) models. However, important data gaps exist for selecting an optimal approach for simultaneously evaluating mutagenicity in both cell types. It is uncertain whether analysis of germ cells from seminiferous tubules (hereafter, tubule germ cells) or caudal sperm within the recommended design for somatic tissues (i.e., 28 days of exposure plus three days of fixation time, 28 + 3d) has enough sensitivity to detect an effect as compared with the analysis of sperm within the recommended design for germ cells (i.e., 28 + 49d and 28 + 70d for mouse and rat, respectively). To address these data gaps, the Germ Cell workgroup of the Genetic Toxicology Technical Committee of the Health and Environmental Sciences Institute reviewed the available TGR mutagenicity data in male germ cells, and, characterized the exposure history of tubule germ cells for different sampling times to evaluate its impact on germ cell mutagenicity testing using TG 488. Our analyses suggest that evaluating mutant frequencies in: i) sperm from the cauda epididymis at 28 + 3d does not provide meaningful mutagenicity data; ii), tubule germ cells at 28 + 3d provides reliable mutagenicity data only if the results are positive; and iii) tubule germ cells at 28 + 28d produces reliable positive and negative results in both mice and rats. Thus, the 28 + 28d regimen may provide an approach for simultaneously assessing mutagenicity in somatic tissues and germ cells from the same animals. Further work is required to support the 28 + 28d protocol for tissues other than slowly proliferating tissues as per current TG 488. Finally, recommendations are provided to guide the experimental design for germ cell mutagenicity data for regulatory submission, as well as other possible approaches to increase the reliability of the TGR assay.