The Treatment Of Intestinal Barrier Dysfunction Induced By Repeated Restraint Stress In Mice

Background：Intestinal barrier, having physical, chemical immune and biologicalfunctions, is the first line in the defense of luminal pathogens. Repeated restraintstress (RRS) induces mouse intestinal barrier dysfunction. Hypoxia-induciblefactor-1α (HIF-1α) plays an important role in the regulation of intestinal barrier.Inhibition of HIF prolyl hydroxylase (PHD) is an effective way to attenuateintestinal disease symptoms in mouse models. Exercise induces gastric ischemia,leading to intestinal tissue hypoxia. Mild to moderate exercise has also been appliedto treat intestinal disease in mouse models. Therefore, we hypothesize that PHDinhibitor and moderate exercise physiologically enhance the level of HIF in intestineand attenuate the intestinal barrier dysfunction induced by RRS.Methods：The aim of this study was to examine the effect of injection PHD inhibitordimethyloxalylglycine (DMOG) and moderate exercise on RRS induced intestinalbarrier dysfunction mouse models, explore possible mechanisms and applicationvalue, and open new window for the treatment of intestinal barrier dysfunctioninduced by chronic stress. Male Balb/c mice (6weeks) were randomized into14groups: CON functioned as controls with no intervention; RRS was subjected to6hper day RRS for7consecutive days; RRS+SWIM, RRS+DMOG and RRS+PBSreceived30min per day of swimming, intraperitoneal injections of DMOG orphosphate buffered saline (PBS) prior to RRS; CON+SWIM, CON+DMOG andCON+PBS only received30min per day of swimming, intraperitoneal injections ofDMOG or PBS for7consecutive days; and the other6groups received one sessionof30min swimming or intraperitoneal injections of DMOG prior to sacrifice at1-,3-and6h recovery. Small intestine segments were excised and stained withhematoxylin-eosin and alcian blue-periodate acid schiff. Intestinal permeability wasquantified with FITC-dextran. Bacterial translocation was determined byquantification of bacterial colony forming units in cultured mesenteric lymph nodes,and with fluorescence in situ hybridization. Antimicrobial related gene expressionwas tested by quantitative real-time polymerase chain reaction. Bacterial structurewas examined by ERIC-PCR. Intestinal Immunoglobulin A (IgA) and selectedantimicrobial peptides concentrations were detected using enzyme-linkedimmunosorbent assay.Results：RRS induced intestinal barrier dysfunction in mouse model: weight loss,changing bacterial structure, reducing the thinness of mucosal layer, increasinghistological damage scores, intestinal permeability and bacterial translocation. Thirty minutes per day of swimming and DMOG administration before RRS, increasingintestinal HIF-1α protein levels, attenuated RRS-induced changes in weight loss,histology, intestinal permeability, bacteria translocation, antimicrobial-related geneexpression, and IgA levels. Gene expression and protein levels for four antimicrobialpeptides (α-defensin5, β-defensin1, and RegIIIβ) were significantly increased afterone session of30min swimming or DMOG injection, and not depended onactivating pattern recognition receptors by bacterial invasion.Conclusion：In conclusion, moderate exercise and HIF PHD inhibition attenuatedRRS-induced intestinal barrier dysfunction in mice, possibly due to augmentation ofantimicrobial responses in the small intestine.