Since it was introduced 20 years ago, tamoxifen-inducible genetic recombination in vivo has become a standard tool in many fields. This technique has great utility, allowing precise temporal and spatial gene recombination mediated by expression of a Cre recombinase-oestrogen receptor hormone binding domain fusion protein. It is frequently used in developmental biology, either for accurate spatio-temporal gene deletion or for lineage-labelling. Administration of high doses of tamoxifen can rapidly induce abortion in pregnant mice but this can be partially overcome by progesterone co-administration. However, administration of tamoxifen to pregnant mice early in pregnancy may have potentially lethal effects on the mother independently of abortion, and can also severely perturb embryonic development. Despite this, only a few published studies mention this fact in passing, and standard parameters for successful or unsuccessful use of tamoxifen in pregnant mice have not been reported. Therefore, in the interests of providing a framework for more humane animal research, we describe our experiences of tamoxifen administration during early gestation in mice. These observations should assist the design of future studies in accordance with the principles of the three Rs (Replacement, Reduction and Refinement of Animals in Research).

中文翻译：

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在怀孕小鼠中给予他莫昔芬可能对母亲和胚胎都有害。

自 20 年前推出以来，他莫昔芬诱导的体内基因重组已成为许多领域的标准工具。该技术具有很大的实用性，允许精确的时空基因重组由 Cre 重组酶-雌激素受体激素结合域融合蛋白的表达介导。它经常用于发育生物学，用于准确的时空基因缺失或谱系标记。给予高剂量的他莫昔芬可迅速诱导怀孕小鼠流产，但这可以通过黄体酮联合给药部分克服。然而，在怀孕早期给怀孕的小鼠服用他莫昔芬可能会对母亲产生潜在的致命影响，而与流产无关，并且还会严重干扰胚胎发育。尽管如此，只有少数已发表的研究顺便提到了这一事实，并且尚未报道在怀孕小鼠中成功或不成功使用他莫昔芬的标准参数。因此，为了为更人道的动物研究提供一个框架，我们描述了我们在小鼠妊娠早期给予他莫昔芬的经验。这些观察结果应有助于根据三个 R（研究中动物的替代、减少和改进）的原则设计未来的研究。