The Association Of MYO9B Gene Polymorphism And The Intestinal Permeability In Inflammatory Bowel Disease And Its Effect By Cyclosporin A

Objective To investigate the association between myosin IXB (MYO9B) genepolymorphism(rs962917,rs1545620)and inflammatory bowel disease(IBD).Methods With collecting the clinical date of IBD patients，Polymerase chain reaction(PCR) and ligase detection reaction (LDR) were used to analyze the MYO9B genepolymorphism of IBD. The controls were gender and age-matched to cases.Detected theconcentration of lactulose and mannitol in urine of118IBD patients by HPLC-PEDmethod.Results (1)Clinical Analysis of UC: The ratio of male to female was1.5:1in100UC.The mean age of cases was43.64±13.69years old. The most of patients was extensivecolitis (53%),32%of patients had proctitis or proctosigmoiditis,15%were diseased tothe splenic flexure; UC is given priority to with moderate activity(41%),23%ofpatients had mild activity, severity disease was33%,3%of patients was remission.(2)Clinical Anaysis of CD: There were96cases of CD. the ratio of male to female was1.9:1and the mean age of cases was36.45±9.85years old.The most localization of CDwas ileum (67.7%),11.5%of patients Located in the colon,18.7%were diseased to theileo-colon, upper GI tract was15.6%. Disease behaviour was nonstricturing，nonpenetrating in30patients(31.2%)，structuring in48patients(50%)，and penetratingin18patient(18.8%). In all the patients，perianal lesions was18.2%.(3) The genotypeof MYO9B analysis: there was no significant difference of genotype frequency andallelic frequency of MYO9B between IBD and normal population; rs962917and rs1545620polymorphism may be associated with the duration, meanwhile, rs1545620polymorphism was found associated with the perianal disease of CD patients. Thepolymorphism of rs962917and rs1545620loci did not correlate with disease duration,activity and lesion site of UC patients.(4) Correlation analysis of MYO9B genepolymorphism and IBD patients intestinal mucosal permeability: The lactulose/mannitolratio in118IBD patients was0.105±0.099，it was significantly higher than that incontrol (0.020±0.002，P<0.05).Conclusions rs962917and rs1545620polymorphism was not associated with thepathogenesis of IBD in China. Balckground Intestinal mucosa barrier including mechanical barrier, immune barrier,biological barrier, chemical barrier, etc, it plays a pivotal role in preventingmicroorganism and toxinum from invading into organism. Intestinal mucosa barrier isimpaired obviously in inflammatory bowel disease,as a result, a large quantity ofintestinal bacteria and endotoxin through the impaired intestinal mucosa barrier induceintestinal inflammation and damage. Restoring the impaired intestinal mucosa isbeneficial for controlling or relieving the inflammation and immunologic reaction,ameliorate intestinal mucosal permeability, to prevent the occurrence of complicationsin IBD. Phosphorylation of myosin light chain by myosin light chain kinase lead tocontraction of the cytoskeleton is a essential condition in the intestinal epithelial barrierdamage. Cyclosporin A as an immunosuppressive agents, play an important role inclinical treatment. However, whether CsA could ameliorate intestinal mucosalpermeability is still unknown. Therefore, the research was to study the effect of CsA onintestinal mucosal permeability of experimental colitis.Aim To establish the C57mice model of UC induced by dextran sulfate sodium (DSS)and investigate the effect of Cyclosporin A（CsA）treatment on the intestinal mucosalpermeability of experimental colitis and its possible mechanism.Methods To establish the mice model of DSS: mice were divided randomly into threegroup: normal group, DSS group, CsA group. DSS group and CsA group were allowedto drink water containing5%DSS freely for7days. Effect of cyclosporin A on the intestinal mucosal permeability of colitis in mice：CsA was injected intraperitoneally atdoses of25mg/kg once a day from d1to d7，normal saline was injected intraperitoneallyin normal group and DSS group. The disease activity index score was evaluated, and thecolon tissue was collected for the assessment of histological changes. The activity ofmyeloperoxidase (MPO), and the levels of TNF-α, interferon-γ(IFN-γ), interleukin-13(IL-13) and interleukin-17(IL-17) in the colon were determined. The small intestinalmucosal was ultrastructurally examined with transmission electron microscopy, and theintestinal permeability was assayed using the FITC-dextran and Evans blue method, thesmall intestine mucosa was collected to determine epithelial myosin light chain kinaseenzymatic activity and expression.Results In order to verify the model, the disease activity index (DAI) score wasevaluated every day,colon tissue was collected for assessment of histological changesby HE, and homogenated for assessment of MPO activity at the end of the experiment.CsA was found effective in reducing the DAI score and the histological index (HI) score,and decreasing the activity of MPO, the levels of TNF-α, IFN-γ, IL-13and IL-17incolitis mice.The small intestinal mucosal injury was ameliorated by CsA and the amountof FD-4permeating into blood and EB permeating into the intestinal wall weredecreased by CsA in colitis mice. Moreover,the small intestinal epithelial MLCKenzymatic activity and expression were downregulated by CsA.Conclusion CsA showed a significant anti-colitis effect.The mechanism of this effectmight be associated with the inhibition of MLCK to ameliorate the intestinal mucosalpermeability.