Effects of psychological stress on gene expression in the mouse rectum.

Using isolation stress model, we showed that goblet cell-dependent mucosal barrier functions in the mouse rectum was more vulnerable to stress than the colon. We also found that isolation stress specifically stimulated IL-18 production only in the rectum. Furthermore, the crucial role of IL-18 in the stress response of the mouse rectum was confirmed using IL-18 knockout mice. Microarray analysis was used to assess the stress response and to identify responsible genes for the vulnerability of the mouse rectum to isolation stress. Total RNA was prepared from the colon and the rectum of wild-type and IL-18 knockout mice before isolation and 8 days after starting isolation. The one GSM sample of microarray analysis was made by pooling an equal amount of total RNA 5 mice of each group. Agilent whole mouse genome oligonucleotide microarray was used to measure gene expression in these samples according to the manufacture’s protocol.