Changes of serum glucagon-like peptide-1 and colonic glucagon-like peptide-1 receptor in rat models of irritable bowel syndrome subtypes
LI Zheng-yang, CHEN Yan, LIN Lin, WANG Mei feng, HAO Bo, ZHANG Hong-jie
Published 2012-04-15
Cite as Chin J Dig, 2012,32(04): 249-255. DOI: 10.3760/cma.j.issn.0254-1432.2012.04.008
Abstract
Objective To investigate the changes of serum glucagon-like peptide (GLP)-1 and colonic GLP-1 receptor in rat models of irritable bowel syndrome (IBS) subtypes and to explore the role of GLP-1 and its receptor in the pathogenesis of IBS.Methods Forty male SD rats were equally divided into D-IBS group,enema control group (D-IBS control group),C-IBS group,gavage control group (C-IBS control group) and blank control group.The D-IBS model was created by the method of acetic acid and restraint stress.The C-IBS model was created by ice water gavage.Changes in rat feces were observed,the weight and water content of feces and the advance rate of rat small intestinal transit were detected. The colorectum was given distension (CRD) stimulation,the electrical activity of external oblique (EMG) was recorded and the visceral sensitivity of rats model was evaluated.The content of active GLP-1 in serum was detected by ELISA in each group. The distribution and expression of GLP-1 receptor in rat proximal colon and distal colon tissue of each group were detected by immunohistochemistry,real-time PCR and Western blot. Results Compared with respective control group and blank control group,the wet weight and water content of feces and the advance rate of rat small intestinal transit all increased (P＜0.05) in D-IBS group.However,the wet weight and water content of feces and the advance rate of rat small intestinal transit all decreased (P＜0.05) in C IBS group.At the pressure of 20,40 and 60 mm Hg (1 mm Hg=0.133 kPa) colorectal distension stimulation,the amplitude of the external oblique discharge significantly increased in model groups compared with their control groups,and which was higher in D-IBS group than that of CIBS group (P＜.0.05).The level of active GLP-1 in serum was higher in C-IBS group than in D-IBS group (P＜ 0.05).There was no significant difference between IBS group and control group.GLP-1 receptors mainly distributed in the colon mucosa,circular muscle and myenteric nerve plexus.The expression of GLP-1 receptor at mRNA and protein level was significantly higher in colon tissue of C-IBS group than that of control gronp,however which was lower in D-IBS group than that of control group (P＜0.05).Conclusions In colon tissue,the expression of GLP-1 receptor was different in (l)BS subtypes,and the serum GLP-1 level was also different,which indicated that GLP-1 and its receptor might be related with palhogenesis of IBS subtypes.
Key words:
Irritable bowel syndrome; Glucagon-like peptide 1; Receptors,glucagon; Viscera; Colon; Disease models,animal
Contributor Information
LI Zheng-yang
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
CHEN Yan
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
LIN Lin
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
WANG Mei feng
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
HAO Bo
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
ZHANG Hong-jie
Department of Gastroenterology, the First Hospital Affiliated of Nanjing Medical University, Nanjing 210029,China
