Department of Biosciences and Neuroscience Center, University of Helsinki, Helsinki, Finland.
PLoS One. 2011;6(9):e24755. doi: 10.1371/journal.pone.0024755. Epub 2011 Sep 8.
Housing conditions represent an important environmental variable playing a critical role in the assessment of mouse behaviour. In the present study the effects of isolation and nesting material on the behaviour of female C57BL/6J mice were evaluated. The mice were subjected to different rearing conditions from weaning (at the age of 3 weeks). The study groups were group- and single-housed mice, divided further into groups with or without nesting material (species-specific enrichment). After 8 weeks spent in respective conditions the behavioural testing began. Both factors (social conditions and nesting material) appeared to have a significant impact on the behavioural phenotype. However, it is important to stress that the interaction between the factors was virtually absent. We established that isolation increased locomotor activity and reduced anxiety-like behaviour in several tests of exploration. In contrast, absence of nesting material increased anxiety-like behaviour. Neither factor affected rota-rod performance, nociception and prepulse inhibition. Contextual fear memory was significantly reduced in single-housed mice, and interestingly, in mice with nesting material. Cued fear memory was reduced by single-housing, but not affected by enrichment. Mice from enriched cages displayed faster and better learning and spatial search strategy in the water maze. In contrast, isolation caused significant impairment in the water maze. In conclusion, both isolation and species-specific enrichment have profound effects on mouse behaviour and should be considered in design of the experiments and in assessment of animal welfare issues.
住房条件是一个重要的环境变量，对评估小鼠行为起着关键作用。本研究评估了隔离和筑巢材料对 C57BL/6J 雌性小鼠行为的影响。从断奶（3 周龄）开始，这些小鼠就处于不同的饲养条件下。研究小组将这些小鼠分为群体饲养和单独饲养的小鼠，然后进一步分为有或没有筑巢材料（特定物种的丰容）的组。在各自的条件下生活 8 周后，开始进行行为测试。这两个因素（社会条件和筑巢材料）似乎都对行为表型有显著影响。然而，需要强调的是，这两个因素之间几乎没有相互作用。我们发现，隔离会增加运动活动，并减少几种探索性测试中的焦虑样行为。相反，缺乏筑巢材料会增加焦虑样行为。这两个因素都不会影响转棒测试的表现、伤害感受和条件反射抑制。在单独饲养的小鼠中，情景性恐惧记忆显著降低，有趣的是，在有筑巢材料的小鼠中也是如此。在条件恐惧记忆中，单独饲养会降低，而丰容则不会。来自丰容笼的小鼠在水迷宫中表现出更快、更好的学习和空间搜索策略。相比之下，隔离会导致水迷宫中的显著损伤。总之，隔离和特定物种的丰容都会对小鼠的行为产生深远的影响，因此在设计实验和评估动物福利问题时应考虑到这些因素。
