Roles Of The Changes Of The ICC And Inflammatory Cytokined In PI-IBS

ObjectiveThe purpose of this study was to establish post-infectious irritable bowelsyndrome (PI-IBS) animal model using C57BL\6mice induced byTrichinella Spiralis; To evaluate visceral hypersensitivity and intestinalmotility in this mouse model and detect the changes and relationships ofthe c-kit, interleukin-1β (IL-1β), IL-17, IL-10and interferon-γ (IFN-γ) indifferent bowel segments, and further to study the roles of the changes ofinterstitial cells of Cajal (ICC) and inflammatory cytokines in themechanism of PI-IBS.Methods1. Establishment of PI-IBS mouse model: A total of34femaleC57BL/6mice were randomly assigned to PI-IBS group (n=17) and controlgroup (n=17). Mice of the PI-IBS group were infected by the oraladministration of400larvae in0.2ml of normal saline, control micereceived only salt solution.2. Hematoxylin-eosin staining (HE staining): Duodenum, jejunum,terminal ileum and proximate colon were processed for pathological examination at day14,28and56post-infected (PI) to observe theinflammation alterations.3. Evaluation of visceral hypersensitivity and intestinal motility: Atday56PI, abdominal withdrawal reflex (AWR) scores, intestinetransportation time (ITT), and the grain numbers, Bristol scores, wet/dryweights, percent water contents of the mice feces every2hours were toassess the changes of the visceral hypersensitivity and intestinal motility.4. To detect the c-kit protein and inflammatory cytokines, enzymelinked immunosobrent assay (ELISA) and western blotting were used tomeasure the levels of IL-1β, IL-10, IL-17, IFN-γ and c-kit in differentbowel segments; the location of c-kit and positive cells were detected byimmunohistochemistry staining.5. To measure the message ribonucleic acid (mRNA) of the c-kit andinflammatory cytokines, reverse transcription polymerase chain reaction(RT-PCR) was used to detect the levels of IL-1β, IL-10, IL-17, IFN-γ andc-kit in different bowel tissues.Results1. HE staining showed a marked infiltration by neutrophils in thelamina propria and interstitial edema on day14PI. Infiltration and edemagradually relieved from day14to28PI. At day56PI, no obviousinflammatory infiltrate was observed.2. At distention volumes of0.35ml and0.5ml, the AWR scores in the PI-IBS mice were higher than those in the controls (P<0.01). Compared tocontrol mice, intestine transmit time (ITT) was significant shorter (P<0.01);the grain numbers, Bristol scores, wet weights and percent water contentsof the PI-IBS mice feces every2hours were obviously higher than these incontrol mice (all P<0.05), however, there was no significant difference ofthe dry weights between PI-IBS and control groups.3. Compared to control mice, the levels of IFN-γ, as well as IL-17,were significantly up-regulated in duodenum and ileum (all P<0.05); IL-10were decreased in jejunum, ileum and colon (all P<0.05), however, therewas no significant difference of the IL-1β levels between two groups. Thec-kit levels of all bowel segments in PI-IBS mice were higher than these incontrol group (all P<0.05).4. Immunolabelling showed that the signals of c-kit were mainlydetected in the submucosa and myenteron. The staining scores of all bowelsegments in PI-IBS mice were notably higher than these in control group(P<0.05).Conclusions1. C57BL\6mice infected by Trichinella Spiralis can be acted asPI-IBS animal model, because which can fairly simulate thehypersensitivity and the intestinal motility disorders in PI-IBS patients.2. The alterations of the ICC numbers and the c-kit levels in theintestinal tissues of PI-IBS mice may closely associate with the changes of the visceral sensitivity and intestinal motility.3. The alterations of the inflammatory cytokines levels in the intestinaltissues of PI-IBS mice may be the initial factor leading to the changes ofthe intestinal ICC and participate in the pathogenesis of the PI-IBS.