Effects of Various Cleaning Agents on the Performance of Mice in Behavioral Assays of Anxiety.

Abstract

Cleaning behavioral equipment between rodent subjects is important to prevent disease transmission and reduce odor cues from previous subjects. However, the reporting regarding the cleansing procedures used during such experiments is sporadic and often incomplete. In addition, some investigators are reluctant to clean devices between subjects because they are concerned that animals will react negatively to the smell of the cleansing agents. We hypothesized that mice tested on an elevated plus maze (EPM) soiled with excretions from conspecifics would test as being more stressed than mice tested on the same apparatus that was cleaned between animals. We tested the performance of C57BL/6J mice on an EPM sanitized with 3 common cleaning agents-isopropyl alcohol, chlorine dioxide, and bleach-and on an EPM soiled with rodent urine, feces, and presumably pheromones. We further tested the potentially aversive nature of the cleansing agents by using the classic light:dark box and a 2-choice light:dark box. Our data indicate that cleaning the EPM compared with leaving it soiled did not affect performance in male or female C57 mice, nor did cleaning agent choice. In addition, test subjects did not react to the presence of the cleaning agents when incorporated into the classic light:dark test. However, in the 2-choice light:dark test, mice given the option to avoid an area containing a cleaning agent showed aversion to all 3 agents, when all other conditions were equal. Given the lack of an observable effect of cleaning on EPM performance, we recommend cleaning of the EPM device between C57 mice to minimize the potential spread of disease.