Never replicate a successful experiment? Standardization, heterogenization and reproducibility in animal experiments

繁殖是任何科学方法的基石，特别是在动物研究中，动物的生命非常宝贵。传统上，动物、饲养和测试程序在动物实验中被标准化，以最大限度地提高测试灵敏度并最大限度地减少动物使用，假设这也将保证再现性。然而，通过减少实验内变异，标准化可能会限制对特定实验条件的推断。事实上，我们最近在小鼠中发现，标准化可能会在行为测试中产生虚假的结果，导致重现性差。然而，尽管这些问题得到了广泛的认识，但仍然不清楚如何在一个实验室内进行实验，从而在不同的研究中获得更稳定的结果。为了使研究人群更具代表性，研究中的系统性变异已经提出将异质化（即，异质化）而不是严格的标准化作为提高来自动物实验的研究发现的再现性和转化价值的有力工具。本项目的总体目标是制定和验证可行和有效的异质化战略，动物实验研究结果的可重复性和转化价值。在一系列的预实验中，将调查三种不同的异质化策略，并在测试真实的多实验室环境中的最佳策略之前比较它们的有效性。将用于系统异质化的因素是（i）批次，（ii）白天时间和（iii）实验者，因为已知所有三个因素都会极大地影响实验的结果。为了模拟基因型效应，将在一组六种不同的行为测试中检查三种常用的近交系小鼠（C57 BL/6、DBA/2、Balb/c）。由于有限的再现性和翻译失败已特别讨论的行为表型研究的背景下，我们将限制我们的分析行为的结果措施。基于以前的研究结果，我们假设异质化的实验将产生更稳定的结果比标准化的实验。

Reproducibility is a cornerstone of any scientific method, especially in animal research where the lives of the animals are highly valuable. Traditionally, animals, husbandry and test procedures are standardized in animal experimentation to maximize test sensitivity and minimize animal use, assuming that this will also guarantee reproducibility. However, by reducing within-experiment variation, standardization may limit inference to the specific experimental conditions. Indeed, we have recently shown in mice that standardization may generate spurious results in behavioural tests, accounting for poor reproducibility. However, despite the widespread recognition of these problems, it is still not clear how to conduct an experiment within a single lab that may result in more stable results across studies. With the aim of making study populations more representative, systematic variation within studies (i.e. heterogenization) rather than rigorous standardization has been proposed to be a powerful tool to improve the reproducibility and the translational value of research findings from animal experiments Thus, the overall aim of the present project is to develop and validate practicable and effective heterogenization strategies that may serve to improve the reproducibility and translational value of research findings from animal experiments. In a series of pre-experiments, three different heterogenization strategies will be investigated and compared with respect to their effectiveness before testing the best strategy in a real multi-laboratory-setting. Factors that will be used for systematic heterogenization are (i) batch, (ii) day time, and (iii) experimenter, since all three factors are known to greatly influence the outcome of an experiment. To mimic a genotype effect, three commonly used inbred strains of mice (C57BL/6, DBA/2, Balb/c) will be examined in a battery of six different behavioural tests. Since limited reproducibility and translational failures has been particularly discussed in the context of behavioural phenotyping studies, we will restrict our analysis to behavioural outcome measures. Based on previous findings, we hypothesize that heterogenized experiments will yield more stable results across experiments than standardized ones.