Faculty of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany.
Altern Lab Anim. 2009 Dec;37(6):641-56. doi: 10.1177/026119290903700609.
The use of experimental animals in reproductive toxicity testing is critically reviewed on the occasion of the 50th anniversary of the publication of the Three Rs concept by Russell and Burch, since there is major concern that reproductive toxicity testing will significantly increase due to the requirements of the EU Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) system. A comparison of the test guidelines for drugs, agrochemicals and industrial chemicals shows that, for historical reasons, significantly different testing strategies are applied. The current status of development and validation of in vitro tests in reproductive toxicology is also critically evaluated. The mouse embryonic stem cell test (mEST) is the most advanced and promising of the in vitro tests. Although it has not yet been accepted for regulatory purposes, its use in preclinical drug development is well established. Moreover, promising molecular endpoints have been established in the mEST, including proteomic and toxicogenomic endpoints. Preliminary results have been obtained with a human EST (hEST). In addition, an overview is given on new in vitro reproductive toxicity tests that are currently being developed in the EU FP6 project, ReProTect, since the ReProTect test battery, which covers the essential steps of female and male fertility, implantation and embryotoxicity, holds promise for use as a screening assay for reproductive toxicity testing according to the EU REACH legislation. However, since validated in vitro methods will not be available in the short term, opportunities for the refinement of the standard in vivo tests are discussed, in order to reduce the numbers of animal used in reproductive toxicity testing. Finally, recommendations for toxicity testing in the 21st century call for the harmonisation of test methods across all areas of regulatory testing as a first step. Since the REACH system testing framework for industrial chemicals is driven by the reproductive safety testing requirements of agrochemicals, a shift is proposed to exposure-driven testing of industrial chemicals. In particular, the implementation of a new 'extended one-generation reproductive toxicity study' (EOGRTS), which includes triggers for additional testing for fertility, developmental neurotoxicity and immunotoxicity, would significantly reduce test animal numbers. It is concluded that in vitro methods hold great promise for reproductive toxicity testing in the 21st century, e.g. the ReProTect in vitro battery and the embryonic stem cell (ESC) technology focusing on molecular endpoints in both the mEST and the hEST.
在 Russell 和 Burch 出版“3R 原则”50 周年之际，对生殖毒性测试中实验动物的使用进行了批判性审查，因为人们主要担心生殖毒性测试由于欧盟注册、评估、授权和限制化学品（REACH）系统的要求，将会显著增加。对药物、农药和工业化学品的测试指南进行了比较，结果表明，由于历史原因，应用了明显不同的测试策略。还批判性地评估了生殖毒理学中体外测试的当前发展和验证现状。最先进和最有前途的体外测试是小鼠胚胎干细胞测试（mEST）。尽管它尚未被接受用于监管目的，但它在临床前药物开发中的应用已经得到很好的证实。此外，在 mEST 中已经建立了有前途的分子终点，包括蛋白质组学和毒理基因组学终点。初步结果已经在人胚胎干细胞测试（hEST）中获得。此外，还概述了目前正在欧盟 FP6 ReProTect 项目中开发的新的生殖毒性体外测试，因为 ReProTect 测试组合涵盖了雌性和雄性生育力、着床和胚胎毒性的基本步骤，有望根据欧盟 REACH 法规用作生殖毒性测试的筛选试验。然而，由于短期内无法获得经过验证的体外方法，因此讨论了对标准体内测试进行改进的机会，以减少生殖毒性测试中的动物数量。最后，对 21 世纪毒性测试的建议呼吁在所有监管测试领域协调测试方法，作为第一步。由于工业化学品的 REACH 系统测试框架是由农药的生殖安全性测试要求驱动的，因此建议转向工业化学品的暴露驱动测试。特别是，实施新的“扩展一代生殖毒性研究”（EOGRTS），其中包括对生育能力、发育神经毒性和免疫毒性进行额外测试的触发因素，将大大减少试验动物的数量。结论是，体外方法在 21 世纪的生殖毒性测试中具有很大的前景，例如 ReProTect 体外电池和胚胎干细胞（ESC）技术，重点关注 mEST 和 hEST 中的分子终点。
