Change And Significance Of Toll Like Recepter-4 Expression In Gut-derived Systemic Imflammation

In order to investigate the role and significance of Toll-like receptor-4 expression in rats treated by partial intestinal ischemia-reperfusion injury,we observe the change of TLR4 expression level in multiple organs in intestinal ischemia / reperfusion injury rats,and survey the relationship between TLR4 expression level and imflammation factors.The experiment are to be excuted by two sections as follows:Part One.Changes and significance of Toll-like receptor-4 gene expression in ileum ischemia / reperfusion injury ratsObjective To investigate the changes of TLR4 expressionin in ileum in rat after partial intestine ischemia/reperfusion(I/R)injury,and the relationship between TLR4 gene expression and TNF-α,IL-6 level in blood of portal vein.Methods A totol of 90 adult male SD rats were randomized into 3 groups:normal control group(n=10),sham-operated group(n=40)and ilem ischemia / reperfusion group(n=40).Animals were sacrificed after being suffered from ileum ischemia/reperfusion injury for 6h,12h,24h and 48h,The expression of TLR4 mRNA was determined with RT-PCR. Meanwhile,blood in portal vein was obtained to assay TNF-αand IL-6 concentration in plasma.Correlation analysis between TLR4 mRNA and TNF-α,IL-6 levels was made.Expression of TLR4 in ileum was evaluated with immunohistochemistry.Results The expression of TLR4mRNA in ileum and TNF-αand IL-6 level in portal vein plasma were significantly higher in experimental group,compared with sham group(P＜0.05) TLR4mRNA expression peaked at 12h after I/R injury,TNF-αand IL-6 concentration peaked at 24h.TLR4mRNA expression and TNF-αand IL-6 level showed significant relativity(r=0.773 and 0.790). Immunohistochemical exam showed TLR4 mainly expressed in ilem mucous membrane.Part Two:Changes and roles of Toll-like receptor 4 expression in multiple organs of rats treated by intestinal ischemia- reperfusion injuryObjective To investigate the changes of TLR4 expressionin in ileum in rat after partial intestine ischemia/reperfusion(I/R)injury,and the relationship between TLR4 gene expression and TNF-α,IL-6 level in blood of portal vein.Methords Intestinal ischemia- reperfusion injury models were established.35 SD rats were randomly divided into three groups, respectively:control group(n=5)and sham-operated group(n=5)and ilem ischemia/reperfusion group(n=5)of 6,12,and 24h.The pathomorphological changes of intestine,lung,liver were observed. Semi-quantitative RT-PCR was used to measure mRNA expression of TLR4 in intestine,lung and liver tissues.Results After intestinal ischemia reperfusion injury to rats,the expression of TLR4 in intestinal,lung and liver increased,especially in intestine and reached to the peak level at 12h.The expression of TLR4 mRNA increased to the peak level in tissues at 12h after injury(P＜0.05 or P＜0.01).The expression of TLR4 mRNA increased most in intestinal tissue.Conclusion1.Expression of TLR4 in ileum was up-regulated after intestine I/R injury in rat,it result in gut barrier dysfunction and being the trigger of following systemic inflamatory response syndrome(SIRS).2.Intestinal ischemia reperfusion injury lead to multiple organs injure in rats.The organs were seriously injured.That TLR4mRNA expression increased in lung,intestine,liver and kidney,and being increased most in intestine,expression of TLR4 may play an important role in pathogenesis of MODS rats induced by intestinal ischemia reperfusion injury.