An Experimental Study On The Protective Effect Of 17β-Estradiol On Liver Graft Against IRI In Rat OLT Model

PART I: Establishing a modified OLT model in ratsObjective: To establish an animal model of modified two-cuff technique orthotopic of liver transplantation in rat.Methods: By practice,120 cases of rat orthotopic liver transplantation were per- formed using the two-cuffed technique with some modification in recipient and donators anesthesia, graft harvesting, the anastomoses of suprahepatic vena cava and the perioperative treatment. the postoperative syndrome and survival rates were investigated .Results: Among the latter 40 cases, the mean time of anhepatic period was 15 minutes, and the mean operation time was 45 minutes .The achievement ratio of operation was 95% and 2 weeks survival was 90%.Conclusions: The modified two-cuffed methods is convenient and easy to duplicated. It can enhance the stability and survival rate of rat orthotopic liver transplantation models.PART II: The protective effect of 17β-Estradiol on liver graft against IRI in rat OLT modelObjective: To estimated the protection of liver graft against ischemia-reperfusion injury in rat orthotopic liver transplantation by use of 17β-EstradiolMethods: 18 couples of SD male rats ,weighed 180～220g, were randomized into three groups. A:group of ischemia-reperfusion; B: group of ischemia- reperfusion + 17β-Estradiol(100ug/kg); C: group of ischemia- reperfusion + 17β-Estradiol(500ug/kg). 17β-Estradiol(100ug/kg/day) was used seven days by peritoneal injection in B receptor group before operation ,In C receptor group ,17β-Estradiol(500ug/kg/day) was used seven days by peritoneal injection before operation. In A receptor group ,the same solvent was used seven days by peritoneal injection before operation. Then perform transplantation of liver by modified two-cuffed methods. The bile output was observed in three groups of liver grafts after portal vein reperfusion .Six hours after reperfusion , the recipients were sacrificed , serum ALT,AST,concentration of Estradiol were measured .liver ultrastructure were observed by electron microscopy, apoptosis of the hepatocytes was analyzed by TUNEL and NF-κB,TNF-α,levels were detected by immunohistochemistry. Serum MDA and MPO were measured by chemical method.Results: Serum concentration of Estradiol increased by turns in A,B and C group. The Serum concentration of Estradiol in different group was significantly different in statistics(P<0.05). The bile output in C and B group was significantly higher than A group,especially higher in B group(P<0.05). Serum ALT,AST levels in B and C group were significantly lower than those in A group ,especially lower in B group(P<0.05).Serum MDA and MPO levels in B and C group were significantly lower than those in A group ,especially lower in B group(P<0.05). In TUNEL analysis, the number of apoptosis in B and C group was markedly decreased compared with A group, especially in B group. Immunohistochemistry study showed the TNF-αand NF-κB level in A group was significantly higher than in B and C group, and most lower in B group. In electron microscopy, the hepatocytes injury in the A group were significantly serious than in the B group and C group.Conclusions: 1. Estradiol can decrease ischemia-reperfusion injury in rat liver transplantation. 2. The protective mechanism of Estradiol in rat liver transplantation may be:①Restraining TNF-αand NF-κB expression.②Inhibiting aggregate on and activation of neutrophilic leukocyte.③by reducing the degree of lipid preoxidation 3. Proper serum concentration of estrogen may exert optimal protective effect on Liver I/R injury in rats.