The Effects And Significances Of Cytokines On Intrahepatic Bile Duct Epithelial Cell Injury During The Cold Preservation Of Liver Graft

With the development for technology, liver transplantation hasbecome the only definitive method of therapy for patients with end-stageliver diseases. However, the morbidity of ischemic-type biliary lesion(ITBL) after liver transplantation has kept in high level for long time. TheITBL seriously impacts survival rate and life quality of the recipientswith liver transplantation. Many specialists have been payed moreattention to the study on ITBL. However the cause of ITBL is still unclear.It is believed that Biliary epithelial cell (BEC) is the primary target ofcold preservation/reperfusion injury (CP/RI), as BEC is more sensitive tothis kind of injury than hepatocyte. After long duration of coldpreservation of allograft, even liver function can keep good statesfollowing transplantation, but the incidence of ITBL is greatly increased.Cold preservation will cause biliary epithelium necrosis and fibrosis, andfollowed by biliary sludge and stricture, thus causes ITBL.It has been found that the obstruction of hepatic tissue, smicrocirculation play an important role in liver CP/RI. But people haveneglected the CP/RI to biliary microcirculation presently, we don’t knowwhether cold preservation/reperfusion will cause the obstruction of biliarymicrocirculation, The relationship among the extent of biliarymicrocirculation vascular endothelial cell injury, microcirculationobstruction and biliary injury, is unclear. In clinical liver transplantation,the system of biliary circulation flushed deficiently and hepatic arteryobstruction following transplantation will cause serious biliary injury andITBL.The aim of our study was to evaluate the effects of cold preservationon intrahepatic biliary microcirculation, and to investigate therelationship between the microcirculation obstruction and intrahepaticbiliary duct injury. PartⅠ A study on model of rat orthotopic livertransplantation for research of intrahepatic biliary CP/RIOBJECTIVETo develop a model of liver transplantation in rats to study theimpact of prolonged cold preservation time on bile ducts after livertransplantation.Materials and methods120healthy, male, SD rats. According to the cold preservation timeof supplied liver, animals were randomly divided into the2hour coldpreservation (P2h, n=30),8hours cold preservation (P8h, n=40),16hours cold preservation (P16h, n=40) and the control groups (n=10).Ratsin the preservation group were served as donor and recipients. The donorliver were preserved at UW solution at4℃for2、8、16hours andtransplanted to the recipients. Based on the classic “two cuff” techniquefor orthotropic liver transplantation, end-to-end anastomosis between thecommon hepatic artery of donor and recipient by the modified “Gaostent” was performed to reconstruct hepatic artery blood flow.ResultsProlonged cold preservation time can cause the severe bile ductinjury; Bile duct histopathology score showed differences between groupswere significant. The model in rats with grafts undergoing16-hour coldpreservation provides suitable model for studying the effects of coldpreservation on bile ducts after liver transplantation.ConclusionGao，s Rat OLT with modifications is a stable and ideal model for theresearch of intrahepatic biliary CP/RI. Part Ⅱ The effects and significances of cytokines onintrahepatic bile duct epithelial cell injury during the coldpreservation of liver graftObjectiveTo investigate the effects and significances of cytokines onintrahepatic bile duct epithelial cell injury during the cold preservation ofliver graft.Materials and MethodsFor36cases of rats receiving orthotopic liver transplantation wererandomly divided into three experimental groups (cold preservation2h,8h,16h).on the3rd and7th day after the operation., liver tissue sectionswere stained with hematoxylin and eosin for histological examination andthe levels of tumor necrosis factor-α (TNF-α) and endothelin-1(ET-1)and interleukin-6(IL-6) and interleukin-8(IL-8) and interleukin-10(IL-10) in serum were measured for ELISA.Results and ConclusionWith the extension of cold preservation time, the concentration ofcytokines significantly increased (P＜0.05) and the ischemia-reperfusioninjury increased in the transplanted liver. Cytokines injured the vascularplexus around the bile duct in the microcirculation during coldpreservation of liver graft. Histological examination of liver demonstrateddisadvantageous effects of cytokines on intrahepatic bile duct epithelialcell.