Cage change influences serum corticosterone and anxiety-like behaviors in the mouse

Abstract

Environmental variables and husbandry practices can influence physiology and alter behavior in mice. Our study evaluated the effects of cage change on serum corticosterone levels and anxiety-like behaviors in C57BL/6 male mice. We examined the effects of 3 different methods of performing cage transfer and of transferring mice to a clean or a dirty familiar cage microenvironment. The 3 different handling methods were forceps transfer, gentle transfer with gloved hands, and a passive transfer technique that did not involve active handling. Active handling methods and transfer to both clean and dirty cage microenvironments significantly increased serum corticosterone 15 min after cage change; however, at 60 min after cage change, levels were comparable to those of unmanipulated mice. Although the effects were transient, cage change altered anxiety-like behaviors in the open field when behavioral testing was performed on the same day. These results demonstrate that the timing of cage change can influence behavioral results, an effect that is an important consideration for rodent behavioral studies.

Figure 1.

Illustration of experimental design for (A) serum corticosterone level analysis and (B) anxiety-like behavioral assays. OFT, open field test; EPM, elevated plus maze.

Figure 2.

(A) Serum corticosterone levels (mean ± SEM) of clean and dirty bedding transfer groups at 15 min subsequent to cage change. (B) Comparison of serum corticosterone levels (mean ± SEM) associated with individual handling methods at 15 min and 60 min subsequent to cage change. *, Values for forceps and gloves transfer methods significantly (P < 0.05) different at 15 min compared with control value.

Figure 3.

(A) Percentage (mean ± SEM) time spent in the center zone of the open-field test on day 1 of behavioral testing. Handling groups demonstrated a trend toward greater time spent in the center zone (P = 0.10) when compared with the control group in a one-way ANOVA. (B) Percentage time (mean ± SEM) spent in the center zone of the open field comparing combined cage change groups to the unmanipulated control group. *, Value for cage change group significantly (P < 0.05) different from that of control group. (C) Percentage time (mean ± SEM) spent in the open arms of the elevated plus maze on day 2 of behavioral testing.