Impact And Significance Of Hypoxia Preconditioning On The Changes Of Serum Endotoxin And The Expression Of Intestinal TLR4Protein In Orthotopic Liver Autotransplantation In Rats

[Objective]:This thesis is based on the orthopotic liver transplantation model constructed by portal vein perfusion,on the basis of preoperative rats goven hypoxic preconditioning(hypoxic preconditioning,HP). After operation, rats intestinal tissue was sampled to observe the changes of the microstructure and ultrastructure of the intestinal cells under the optical microscopy and transmission electron microscope;blood was drawn to conduct levels of ALT, AST and changes of serum endotoxin; expression of TLR4protein and expression of TNF-α mRNA in intestinal,to observe how HP to influence the level of serum endotoxin and the expression of TLR4protein in intestinal and finally to influence the function of transplanted liver, and then to access that how HP can mitigate the damage of transplanted liver.[Method]1.72Sprague-Dawley rats were randomly divided into the following three groups:normal control group(NC):received no special treatment; autotransplantation group:performed autotransplantation(AT); and hypoxia preconditioning group(HP):rats were given an8%oxygen mixed gas for90minutes before autotransplantation.2. At1,6,12hours after the operation, the rats were sacrificed and the following tests were conducted:(1) blood was drawn to test liver function(ALT and AST);(2) using ELISA kits to measure changes of serum endotoxin;(3) Intestinal tissue was sampled to observe the changes of the microstructure and ultrastructure of the intestinal cells under the optical microscopy and transmission electron microscope;(4)expression of TLR4protein in intestinal was observed with immunohistochemical stains;(5) RT-PCR observe the expression of TNF-a mRNA.[Results]1.Analysis of animals number:all rats were selected result analysis. There were24rats in each group. In each group, eight rats were killed at1,6and12hours after surgery. The criteria for successful operation is that rats immediately regained consciousness, stood up, and to maintain effective breathing, heartbeat after surgery. 2.Serum levels of ALT and ASTThe serum levels of ALT and AST in hypoxia preconditioning group were significantly lower than that of autotransplantation group at1,6and12hours after the orthopotic liver autotransplantation but all higher than that of normal control group.(p<0.01).3. Changes of the microstructure of the intestinal cellsInjury of the Intestinal mucosal of HP group was significantly lighter than that of AT group under the optical microscopy,but all heaver than that of NC group.4. Changes of the ultrastructure of the intestinal cellsInjury of the mitochondria of HP group was significantly lighter than that of AT group under the transmission electron microscopy,but all heaver than that of NC group.5. Level of serum endotoxinThe serum levels of endotoxin of HP group were significantly lower than that of AT group at1,6and12hours after the orthopotic liver autotransplantation,but all higher than that of NC group (P<0.01).6. Expression of TLR4protein in intestinalThe expression of TLR4protein in intestinal of HP group was significantly lower than that of AT group at1,6and12hours after the orthopotic liver autotransplantation,but all higher than that of NC group(P<0.01).The level at different groups has no regulation.7. Expression of TNF-α mRNA in intestinalThe expressions of TNF-α mRNA in intestinal of HP group and AT group begin increasing at1hour and to be the higherest at6hour,then begin decreasing.The expression of TNF-a mRNA in intestinal of HP group was significantly lower than that of AT group at1,6and12hours after the orthopotic liver autotransplantation,but all higher than that of NC group (P<0.01).[Conclusion]:HP can induce the level of serum endotoxin in orthotopic liver autotransplantation in rats by protecting the intestinal mucosa,also induce the expression of TLR4protein in intestinal,thus restraining TLR4signaling pathway, inducing the release of multi-kinds of cytokies like TNF-α and inflammatory mediators,and finally mitigating the damage of transplanted liver.