ABSTRACT
Objective To detect the expression of CRF and CRF receptors in colonic mucosa of DSS induced colitis in mice model and to study the effect of CRF and CRF receptors on the development.Methods Six to eight weeks healthy female BALB/c mice were divided into control group and DSS group.Setting up DSS colitis model and colitis was evaluated by the disease activity index(DAI) and histological score.The immunofluorescence technique was used to assay the CRF1 and CRF2 receptors expression in colonic mucosa.The expression of CRF and CRF receptors protein were analyzed by western blotting.Results DSS colitis was set up successfully with significant inflammation in colonic mucosa by the disease activity index (DAI) and histological score.Immunofluorescenee staining evidenced that expression of CRF1 receptor in DSS colitis group has no significant deviation compared to control group(P ＞ 0.05),while the expression of CRF2 receptor was elevated in DSS colitis group compared to control group (P ＜ 0.05).CRF2 receptor was localized in epithelial cells and mononuclear cells in the lamina propria.The levels of CRF and CRF2 receptor protein by western blotting were higher in in DSS colitis group compared to control group (P ＜ 0.05).The level of CRF1 receptor protein in DSS colitis group had no significant deviation compared to control group(P ＞ 0.05).Conclusion The higher expression of CRF and CRF2 in colonic mucosa of DSS colitis may participate in the development of colitis.
ABSTRACT
OBJECTIVES: Corticotropin releasing factor (CRF) plays a primary role in coordinating the neuroendocrine, autonomic, immune and behavioral responses to stress. CRF exerts its action through two major receptors, corticotropin-releasing factor 1 Receptor (CRF-R1) and corticotropin-releasing factor 2 receptor (CRF-R2). Using two types of chronic stress models, we investigated the changes of CRF-R1 mRNA and CRF-R2A mRNA expressions and CRF mRNA in the stress related brain circuit areas. METHODS: Male Sprague-Dawley rats were exposed to either immobilization stress or variable intermittent unpredictable stress for 10 days and then in situ hybridization histochemistry was used to quantify CRF expression in the brain. RESULTS: 1) CRF1 receptor mRNA expressions were decreased in bed nucleus stria terminalis (BNST) following stressors. 2) CRF2A receptor mRNA expressions were increased in lateral septum following stressors. 3) CRF mRNA expressions were increased in central nucleus of amygdala (CeA) and BNST. CONCLUSION: The increased CRF mRNA of CeA and BNST may be related with anxiety response in the repeated stress. Down-regulation of CRF-R1 mRNA expression in BNST may represent a compensatory adaptation to chronic stress and may be involved in the anxiety response, whereas up-regulation of CRF-R2A mRNA expression in lateral septum may represent an anxiety response or impaired learning but the functional meaning is uncertain.