Assessing the exploratory and anxiety-related behaviors of mice. Do different caging systems affect the outcome of behavioral tests?

Ample studies have shown that housing can affect the health, welfare and behavior of mice and therefore, the outcomes of certain experiments. The aim of this study was to investigate if three widely used housing systems, Open Top Cages (OTC), Motor Free Ventilated Cages (MFVC) and Individually Ventilated Cages (IVC) may affect exploratory and anxiety-related behaviors in mice. Subjects were 8 week-old male C57Bl/6 J mice (n = 36) divided into three groups, OTC, IVC and MFVC groups, respectively. The experimental procedure consisted of two behavioral tests: the open field and the elevated plus maze test. Although there were no differences in the open field test, the results from the elevated plus maze showed that animals housed in the MFVCs exhibited increased exploratory and less anxiety-like behavior. It is concluded that the different caging systems may have an impact on the outcome of behavioral tests used to assess exploratory and anxiety like behavior in mice. Therefore, it is essential to take into consideration housing conditions when reporting, analyzing, and/or systematically reviewing the results of behavioral testing in mice.