Protective Effects Of Metallothionein Induced By Zn～(2+) On Ischemia-reperfusion Injury Of Rat Liver Graft

PART 1:Introducing a modified OLT modelObjective: To search a steady method of orthotopic liver transplantation in rats.Methods: 100 cases of rat orthotopic liver transplantation were performed using thetwo-cuffed technique with some modification in graft harvesting, graft liver perfusing, theanastomoses of suprahepatic vena cava and the perioperative treatment on the basis ofKamada using the cuffed anastomoses of vena. the postoperative syndrome and survivalrates were investigated.Results: In the later of the preliminary test, the mean time of anhepatic period was15rain, and the mean operation time was 45min. The successful rate of operation and 2 weekssurvival rates were 94% and 90% respectively.Conclusions: The modified "two-cuff method" posseses advantages of hign rate of longtime survival and less complication which is a steady operative method of orthotopic livertransplantation in the rat.PARTâ…¡: Protective effects of metallothionein induced by Zn²⁺ onischemia-reperfusion injury of rat liver graftObjective: To estimated the protection of liver graft against ischemia-reperfusioninjury in rat orthotopic liver transplantation by use of zinc.Methods: 12 couples of SD male rats ,weighed about 200～250g, were randomizedinto experimental group and control group. Injecting in the abdominal cavity with 5 mg/kgZnSO₄·7H²O in the experimental group for three days meanwhile coordination quantitynormal saline without ZnSO₄·7H₂O in the control group. Six hours after reperfusion, Thebile output was observed in two groups of liver grafts, the recipients were sacrificed,serum ALT, AST, LDH were measured ,liver ultrastructure were observed by electron microscopy, apoptosis of the hepatocytes was analyzed by TUNEL and FCM, TNF-alevels were detected by immunohistochemistry and metallothionein,T-AOC,, MDA weredetected in two groups.Results:The bile output in the experimental group was significantly higher than incontrol group. Serum ALT,AST,LDH levels in the experimental group were significantlylower than those in control group. The quantity of metallothionein, T—AOC and NO in theexperimental group was higher those in control group,meanwhile the MDA had theadverse result. In electron microscopy ,the hepatocytes injury in the control group weresignificantly more serious than in the experimental group .In TUNEL and FCM analysis,the number of apoptosis in the hepatocytes in the control group was markedly increasedcompared with the experimental group. Immunohistochemistry study showed the TNF-alevel in control group was significantly higher than in experimental group.Conclusions: Metallothionein induced by Zn²⁺ can decrease ischemia-reperfusioninjury in rat liver transplantation. The mechanism may be metallothionein inhibit oxidativeinjuries, protect cell envelope, and maintain steady state of calcium by inducing productionof metallothionein.