Experimental Study On Tolerance Cold Preservation Injury Following Warm Ischemia In Biliary Tract Of Donor Liver

Objective:1. To investigate the tolerance time limits from warm ischemia to cold preservation of liver grafts, and to provide experiment evidence for clinic to avoid the biliary tracts inconvertibility necrosis and primary non-function of liver graft early stage post-transplantation of liver.2. To investigate the mechanism of cold preservation injury following warm ischemia in donor biliary tracts.3. To investigate the relationship between the level of enzyme system in the graft biliary tract effluent and biliary ducts ischemic-injury, and to seek a potential method to evaluate the graft quality before implantation.Methods:The research targets are healthy male SD rats.1. The animal model is liver harvest of rat liver transplantation, and preserved the liver in 0-4℃UW fluid.2. Divide the experimental animals into seven groups (n=24/group) according to the cold preservation time (Oh, 4h, 8h, 12h, 16h, 20h, 24h), and collect the samples at the end of cold preservation, as follow:①collect the graft biliary tract effluent to measure the level of alanine aminotransferase (ALT),aspartate aminotransferase (AST),alkaline phosphatase (ALP) andγ-glutamyltransferase (GGT) in each group;②collect the common bile duct to measure the activity of Na~+ -K~+-ATPase, observe and quantization the injury degree of the epithelial cells of bile ducts in grafts;③collect the donor liver to do pathology examination.3. All the experimental data was analysised by statistic method.Result:1. With the prolongation of liver cold preservation following 10 minutes of warm ischemia, the concentration of ALT,AST,ALP and GGT in the graft biliary tract effluent were increased, compared with the early stage of cold preservation (less than 12 hours group), the concentration of enzyme were significantly elevated in the more than 12 hours cold preservation group (P<0. 01).2. The activity of Na~+,K~+-ATPase of bile ducts in grafts were significantly reduced (P<0.01) with the prolongation of liver cold preservation.3. With the prolongation of liver cold preservation, the injury degree of bile ducts and liver cell in grafts were aggravated gradually, compared with the early stage of cold preservation (less than 12 hours group), the morphological scores of the epithelial cells of bile ducts in grafts were significantly elevated in the more than 12 hours cold preservation group(P <0. 01).Conclusion:1. Within 10 minutes warm ischemic time, bile ducts stored in UW solution within 12 hours cold ischemic time are safety; however, when the cold preservation time exceeded 12 hours, the major injury of bile ducts could be occurred.2. Na~+,K~+-ATPase play a important role in cold ischemia of grafts, and is one of mechanism mediate injury of bile ducts.3. The concentration of enzyme system (ALT,AST,ALP and GGT) in the graft biliary tract effluent can evaluate the quality of donor liver.