Hutchinson Eric K, Avery Anne C, Vandewoude Sue
Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
J Am Assoc Lab Anim Sci. 2012 Jan;51(1):18-24.
The goal of environmental enrichment for laboratory animals is to improve welfare, but some enrichment practices may affect research in unintended ways or even be harmful to the animals themselves. We previously found that mice raised at a commercial vendor then given multiple enrichment devices upon arrival at our facilities experienced thymic atrophy and greater variation in measured parameters than did their unenriched counterparts, suggesting that enrichment conditions affected corticosteroid expression in mice. The current study verified and expanded these results, examining 120 female BALB/c mice raised with or without nesting material at a commercial vendor (n = 60 per group) and allocated (n = 20 per group) to receive no enrichment, nesting material, or 'superenrichment' on arrival at our facilities. Nesting material provided prior to weaning was associated with higher levels of urinary corticosteroid, whereas superenrichment and nesting material during the adult period both led to increased thymic atrophy. Paradoxically, mice that never received enrichment, despite having the lowest corticosterone levels and least thymic atrophy, had increased tail wounds resulting from aggressive interactions. Therefore, enrichment devices that are as seemingly innocuous as nesting material, even if only provided in the preweaning period, may lead to significant, lasting changes in behavioral, physical, or immunologic measures with the potential to alter research outcomes.
对实验动物进行环境优化的目的是改善其福利，但一些优化措施可能会以意想不到的方式影响研究，甚至对动物本身有害。我们之前发现，在商业供应商处饲养的小鼠，到达我们的设施后配备多个优化装置，与未进行优化的同类小鼠相比，它们出现了胸腺萎缩，测量参数的变化也更大，这表明优化条件影响了小鼠体内皮质类固醇的表达。当前的研究验证并扩展了这些结果，研究了120只雌性BALB/c小鼠，这些小鼠在商业供应商处饲养时有无筑巢材料（每组n = 60），到达我们的设施后，将其分配为（每组n = 20）不接受优化、接受筑巢材料或“超级优化”。断奶前提供筑巢材料与较高水平的尿皮质类固醇有关，而成年期的超级优化和筑巢材料都导致胸腺萎缩加剧。矛盾的是，从未接受优化的小鼠，尽管皮质酮水平最低且胸腺萎缩最少，但因攻击性互动导致的尾巴伤口却增加了。因此，像筑巢材料这样看似无害的优化装置，即使仅在断奶前期提供，也可能导致行为、身体或免疫指标发生显著的、持久的变化，从而有可能改变研究结果。
