Expression And Significance Of TLR4, TLR9 In Colonic Mucosa In Mice Colitis

ObjectiveInflammatory bowel diseases (IBD) include ulcerative colitis (UC) and Crohn disease (CD), which have progressively increased in the last 20 years.Despite the etiology and pathogenesis of IBD related to the factors of genetic,environmental,immunologic,infectious causes and etc,but still unsuccess in finding the aetiological culprit.It has been found in recent study that TLR is an important molecular to participate in nonspecific immune response and a bridge from nonspecific to specific immune.Toll-like receptors belongs to a family of type I transmembrane receptors,they bound to pathogen associated molecular patterns(PAMPS),through myeloid differentiation factor 88 and nuclear factor,induce many signal pathways,then initiate cell activation, upregulate major histocompatibility complex(MHC) and costimulatory molecules expression,secrete cytokine and so on.At last,they induce inflammation response.The purposes of this experiment are to study the expression of TLR4, TLR9, NF-κB and TNF-αin colonic mucosa of DSS induced colitis in animal model and its relationship with pro-inflammatory cytokines and its molecular regulatory mechanism, to explore the effects of TLR4 and TLR9 signal pathway on the experimental colitisMethodsSetting up animal model of DSS colitis and evaluating gross changes and histopathology of colon.Six to eight weeks healthy female Balb/c mice were divided into two groups randomly.Group A(n=5):drank distilled water freely.Group B(n=15) were given 5% DSS solution as drinking water for 7 days to induce acute intestinal inflammation and the animals were sacrificed at the 7th day.The expression of TLR4,TLR9,NF-κB and TNF-αbeen detected in colonic mucosa with an immunohistochemical approach.Results:1. Dss murine colitis was set up successfully with significant Inflammation in colonic mucosa by gross and histological examination2. The expression of TLR4 and TLR9 in colonic mucosa by immunohitochemistry in group B was significantly higher than those in group A(P<0.05).Meanwhile the expression of TNF-αin group B was higher than those in group A(P<0.05).Also there was higher expression of NF-κB in group B than this that in group A(P<0.05),and a good positive correlation was found between TLR4,TLR9 and other inflammatory factors.3.There were close compatibility among TLR4 and TLR9 in colonic mucosa.Conclusions1. There were significantly higher expression of TLR4 and TLR9 in the colonic mucosa of DSS-induced murine colitis,which to some extend reflect the degree of inflammation2. The expression of NF-κB and TNF-αwere higher comparing to control group with a paralleled relation to TLR4 and TLR9.The data was reflected the expression of TLR4,TLR9,NF-κB and pre-inflammatory cytokines are correlated closely.The addition effects of them may play an important role in magnifying and sustained inflammation.3. There were close Compatibility among TLR4 and TLR9, suggesting that the two may be synergies from the occurrence and development process of Inflammatory bowel disease. ObjectiveTo characterize the difference of TLR4 and TLR9 in levels of protein expression in epithelium of normal human colon and different severity of UC.To explore the possible effects of TLR4 and TLR9 in the imitation and progression of UC.MethodsThe patients with active UC diagnosed by department of gastroenterology in CHENGDU military general hospital were recruited into this trial.The ulcerative colitis disease activity index (UCAI) was calculated based on clinical data,blood and biochemical parameters and endoscopic features.The pathological grades of UC were classified according to Truelove criteria.The expression of TLR4,TLR9 and NF-κB p65 in colonic tissues of UC and healthy controls were evaluated by immunohistochemistry approach.Results1. The diseased region of UC localized in distal colon,and the disease activity almost was mild to moderate.The score of UCAI have positive correlation with the pathological grade(p<0.05).2. The expressions of TLR4, TLR9 and NF-κBp65 protein in colonic epithelium and inflammatory cells in UC were higher than healthy control by immunochemistry approach.Meanwhile, the positive numbers were increased gradually with pathological grades(p<0.05), and there was direct correlation between expressions of TLR4 and TLR9(p<0.05).Conclusions1. The low or negative expression of TLR4 and TLR9 in colon may participate in the tolerance of colon mucosa to bacteria wall components.However TLR4 and TLR9 in UC-were upregulated significantly,which to some extend reflect the degree of inflammation as well as might contribute to occurrence and development of UC.2.The expression of NF-κB were higher comparing to control group with a paralleled relation to TLR4 and TLR9.The data was reflected the expression of TLR4,TLR9,NF-κB are correlated closely.The addition effects of them may play an important role in magnifying and sustained inflammation of Ulcerative colitis.3. There were close compatibility among the expression of TLR4 and TLR9 in tissue of UC, suggesting that the two may be synergies from the occurrence and development process of Ulcerative colitis.