Augustsson Hanna, van de Weerd Heleen A, Kruitwagen Cas L J J, Baumans Vera
Unit for Comparative Physiology and Medicine, Department of Large Animal Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Lab Anim. 2003 Oct;37(4):328-40. doi: 10.1258/002367703322389898.
Several confounding factors may influence the outcome of an experiment and the extent of inter-individual variation. The aim of this study was to investigate if cage enrichment induces an effect on experimental mean values and on inter-individual variation in the light/dark paradigm using diazepam as the anxiolytic drug. The behaviour of 216 naive adult male mice of two different strains (BALB/c and C57BL/6) was studied. The animals were housed in groups of four in 'non-enriched', 'enriched' (nesting material) or 'super-enriched' (nest-box, nesting material, wooden gnawing stick and PVC tube) cages. After 5 weeks the animals were assigned to one of three treatments: control (no injection), sham (saline injection i.p.) or diazepam (1 mg/kg bw i.p.) and tested in the light/dark test for 5 min. Variation data were analysed using three different methods (mean absolute deviation, coefficient of variation and power analysis). The C57BL/6 mice scored higher than BALB/c mice in activity related measurements and showed a less 'emotional' behaviour profile in the pharmacological control situation of the light/dark test. In this study the anxiolytic effect of diazepam was clear in BALB/c mice but absent in C57BL/6 mice. Mice housed in enriched and super-enriched cages gained more weight than mice in non-enriched cages, although food intake was not affected. Generally, the strain of mouse had the greatest impact on both mean values and variation. However, there was no consistent increase for one particular strain. The choice of statistical method for analysing variation may influence the interpretation of within-group variability, but none of the methods showed any significant differences between standard and enriched conditions on variability in any of the parameters measured.
几个混杂因素可能会影响实验结果以及个体间差异的程度。本研究的目的是调查在明暗实验范式中，使用地西泮作为抗焦虑药物时，饲养环境丰富化是否会对实验平均值和个体间差异产生影响。研究了两种不同品系（BALB/c和C57BL/6）的216只未经过实验的成年雄性小鼠的行为。将动物每四只一组饲养在“非丰富化”、“丰富化”（有筑巢材料）或“超丰富化”（有巢箱、筑巢材料、木制啃咬棒和PVC管）的笼子里。5周后，将动物分为三种处理组之一：对照组（不注射）、假手术组（腹腔注射生理盐水）或地西泮组（腹腔注射1mg/kg体重），并在明暗测试中测试5分钟。使用三种不同方法（平均绝对偏差、变异系数和功效分析）分析变异数据。在与活动相关的测量中，C57BL/6小鼠的得分高于BALB/c小鼠，并且在明暗测试的药理对照情况下表现出较少的“情绪化”行为特征。在本研究中，地西泮对BALB/c小鼠有明显的抗焦虑作用，但对C57BL/6小鼠没有作用。饲养在丰富化和超丰富化笼子里的小鼠比饲养在非丰富化笼子里的小鼠体重增加更多，尽管食物摄入量没有受到影响。一般来说，小鼠品系对平均值和变异的影响最大。然而，没有一个特定品系有持续的增加。分析变异的统计方法选择可能会影响组内变异性的解释，但在测量的任何参数的变异性方面，没有一种方法显示标准条件和丰富化条件之间有任何显著差异。
