Th1/Th2 shift in gut of mouse model of postinfectious irritable bowel syndrome

Abstract

Objective To observe the expressions of Th1 cytokin [interleukin (IL)-12] and Th2 cytokin (IL-4) in gut of the mouse model of postinfcctious irritable bowel syndrome (PI-IBS). Methods Thirty mice were divided into control group (n=8) and model group (n=22,infected with Trichinella spiralis). The weight of the mouse was measured weekly after infection. Visceral sensitivity of colorectal distention in mouse was accessed by abdominal withdrawal reflex (AWR) at 0 and 8 weeks after infection. All mice were sacrificed at the 8th week, and tissues of jejunum, terminal ileum, proximal colon and distal colon were observed for inflammation with HE staining. The mRNA and protein expressions of IL-12 and IL-4 were examined by RT-PCR and Western blotting, respectively. Results Two weeks after infection, body weight was decreased in model group compared with control group ( -1.08%±1.08 % vs 3.09%±1.85%, P 0.05). Severe inflammation was observed in the gut of mouse 2 weeks after infection, however it was recovered at the 8th week. The score of AWR was higher in model group at 30,45 and 60 mmHg in comparison with control group (P<0.05), whereas the perceptual threshold was lower in model group than in the control group (P<0.05). In comparison with control group, increased expressions of IL-12 mRNA and protein in ileocecum and proximal colon as well as decreased expressions of IL-4 mRNA and protein in all parts of gut were found in model group (P<0.05). Conclusion Th1/Th2 shift may involve in gut of PI-IBS mouse, which provides a new idea for treatment of PI-IBS. Key words: Irritable bowel syndrome; Infection; Interleukins