The Experimental Research Of Toll-like Receptor In Mouse Pancreas With Severe Acute Pancreatitis Activated By Exogenous Ligands

ObjectiveSevere acute pancreatitis (SAP) is a dangerous disease which is commonly seen in clinic. Once occurred, there are no effective treatment. The mortality is about 20% to 30%, It can reach to 40% which is reported by abroad. At present, people have discovered lots of factors concerned with SAP. Among those, it is the most important factor that inflammatory mediator, cytokines induce macrophages, neutrophil and vascular endothelial cells excessive activation which can lead to systemic inflammatory reaction. SAP is a systemic disease, it is generally accepted that the disequilibrium theory of cytokine and inflammatory reaction play a very important role in the pathogenesy of the SAP. In 1990's, people put forward the "two-hit" theory for SIRS. To SAP, we can draw the conclusion that various stimulation were regarded as the first-hit to form AEP, proper type antigens were regarded as the second-hit occurring in a certain time-window can initiate cytokine cascade reaction and induce SAP. TLR is a type of cellular membrane receptor family which can mediate inherent immunity found in biosystem in recent years. It can produce marked effect through activate a series of genetic expression. Toll receptor is a kind of mediating inherent immunity cell membrance receptor groups that found in many biosystem in recent years. It produce a marketed effects through activating a series of genes expressions that associating with immunization, the transmission process about TLRs activatied signals main comes from the study of TLR2 and TLR4. After exogenous ligands activating TLRs, It through a series of complicated signal transduction, causes nuclear factor-kappaB(NF-kB)activated, promotes cytokine releasing and finally form SAP. through a series of complicated signal transduction, the experiment through establishing severe pancreatitis test models of rats to observe the second-hit of LPS, BLP that lead to SAP, serum amylyase and the expression of cytokine IL-1βat different time in AP to confirm 'AEP plus second-hit in time-window' creating the theory of SAP. To clarify the effect of TLRs in severe acute pancreastitis through determine the expression of TLRs in pancreatic tissue.Methods60 mouses that weights from 18 to 22 gram are divided into four groups at random. The first group is nomal control, the second is mitis pancreatitis, the third is LPS, and the fourth is LPS plus BLP. Every group is divided into a, b, c, three groups according to different time after injection. Peritoneal injection with induce AP. At the 5, 24, 72 hours after AP to inject LPS, LPS+BLP. or DMEM cell culture medium. To dissect experimental animals after 6 hours. To determine the serum amylase, expression of IL-1βin evry experimental animals. To determine TLR 2, 4 in pancreatic tissue with immunochemistry SP.Results(1) The score of serum amylase and pancreas histological: there are significant statistical significances between the first group and the second group, and between the second group and the third and fourth group. It confimed the model of severe acute pancreatitis was successful.(P<0.01)(2) the expression of serum IL-18: A significant statistical significance between the first group and the second group, and between the second and the third and fourth group.(P<0.01)there is also significant statistical significance between the third and the fourth group.(P<0.05)(3) the comparison from the second group to the fourth group, the expression of IL-18 in 24 hours after AP was the most significant(P<0.05)(4) the expression of TLR2, 4 determined by immunochemistry sp: significant statistical significances are between the first group and the second group, and between the second and the third and fourth group.(P<0.05)Conclusionthe experiment clarifys the theory that 'AEP plus second-hit in time-window' induce SAP. In the early period of AEP, especially in the secretion peak of cytokine at 24 hours, LPS, BLP exciting the development of severe acute pancreatitis was the most manifest, exogenous ligand LPS. BLP cause rat SAP through agitating TLR of pancreas, It was more obviously especially both of them agitate pancreas, the experiment offered a new idea for the pathogenesy, precaution and treat of SAP.