Mouse Genomics Resource Laboratory, National Institute of Genetics, Yata, Mishima, Shizuoka, 411-8540, Japan.
Laboratory of Biochemistry and Toxicology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Yada, Shizuoka, 422-8526, Japan.
Sci Rep. 2017 Aug 1;7(1):6991. doi: 10.1038/s41598-017-07233-5.
Group-housed male mice exhibit aggressive behaviour towards their cage mates and form a social hierarchy. Here, we describe how social hierarchy in standard group-housed conditions affects behaviour and gene expression in male mice. Four male C57BL/6 mice were kept in each cage used in the study, and the social hierarchy was determined from observation of video recordings of aggressive behaviour. After formation of a social hierarchy, the behaviour and hippocampal gene expression were analysed in the mice. Higher anxiety- and depression-like behaviours and elevated gene expression of hypothalamic corticotropin-releasing hormone and hippocampal serotonin receptor subtypes were observed in subordinate mice compared with those of dominant mice. These differences were alleviated by orally administering fluoxetine, which is an antidepressant of the selective serotonin reuptake inhibitor class. We concluded that hierarchy in the home cage affects behaviour and gene expression in male mice, resulting in anxiety- and depression-like behaviours being regulated differently in dominant and subordinate mice.
群养雄性小鼠对其笼内同伴表现出攻击性，并形成社会等级。在这里，我们描述了标准群养条件下的社会等级如何影响雄性小鼠的行为和基因表达。在研究中，每只笼子里饲养四只雄性 C57BL/6 小鼠，并通过观察攻击性行为的视频记录来确定社会等级。形成社会等级后，分析了小鼠的行为和海马基因表达。与优势小鼠相比，从属小鼠表现出更高的焦虑和抑郁样行为，以及下丘脑促肾上腺皮质激素释放激素和海马 5-羟色胺受体亚型的基因表达升高。口服给予氟西汀可缓解这些差异，氟西汀是一种选择性 5-羟色胺再摄取抑制剂类抗抑郁药。我们得出结论，笼内的等级制度会影响雄性小鼠的行为和基因表达，导致优势和从属小鼠的焦虑和抑郁样行为受到不同的调节。
