The Research On Warm Ischemia Injury In The Graft Following Experimental Orthotopic Liver Transplantation

Objective To study the mechanism and effection due to warm ischemia reperfusion injury in graft following orthotopic liver transplantation.Methods The rats were divided into four groups (n=6/group) including the control group that biliary extra-drainage was only performed and 3 liver transplantation groups that warm ischemia time was respectively 0, 5, 10 min (W0,W5,Wio). In all transplantation groups, liver grafts were stored in UW solution (4C) for 6 hours before implantation. Orthotopic liver transplantation with hepatic artery reconstruction and biliary extra-drainage model using inbred male BN rats was established under microscopy. At 24 hours postoperatively, liver samples were collected for histopathological studies and determining the mRNA transcription levels of ICAM-1 with quantitative reserve transcription chain reaction (QRT-PCR). Blood samples were taken simultaneously for measurement of hepatic function, nitric oxide (NO), endothelin-1 (ET-1), malondialdehyde (MDA), superoxide dismutase (SOD). Meanwhile bile was also gotten to assay lactate dehydrogenase(LDH), alanine transaminase(ALT), aspartate transaminase(AST), Y -glutamyltransferase(GGT) and total bilirubin(TBIL).Results Histopathological studies showed remarkable morphological changes were not observed in rats of Group C and Group W0. It was also showed normal hepatic parenchyma and not discovered that damage of hepatocyte, sinusoidal congestion, and neutrophils infiltrating into hepatic tissue. In Group W5, congestedin central vein of hepatic lobule and sinusoid and swelling hepatocyte were exhibited. There were no hepatocytes necrosis and infiltration of neutrophils. It was discovered ballooning hepatocytes, hepatocytes necrosis and neutrophils infiltrating in Group WIQ- Compared with C group, serum AST, ALT, LDH, GGT, alkaline phosphatase(ALP), direct bilirubin(DBIL) were markedly increased in liver transplantation group and positively correlated with liver graft warm ischemia time except for ALP. The serum cholinesterase(CHE) and TBIL were not siginifiantly altered in each group. Compared with C group, ALT,AST, LDH in bile were markedly increased in liver transplantation groups without correlation to warm ischemia time. There was no significantly changing of GGT and TBIL in bile of four groups. In liver transplantation groups, Serum MDA, NO and ET-1 were significantly increased, but SOD activity was decreased markedly. Among those markers, MDA and NO were related with the warm ischemia time, while ET-1 and SOD were not related. Compared with Group C, the mRNA transcription level of ICAM-1 was also marked increasing in liver transplantation groups and positive correlation with graft warm ischemia time.Conclusion Orthotopic liver transplantation with artery reconstruction in inbred rats can embody the warm ischemia of graft in liver transplantation and might be suitable for research on ischemia-reperfusion injury post liver transplantation. Hepatocyte is the main site of warm ischemia injury. With increasing warm ischemia time of graft, the injury of liver graft became crisis. It is demonstrated that serum AST, ALT, LDH could present the degree of warm ischemia injury and might be valuable markers serving as predicting index. Associated with the increasing warm ischemia of graft, cholestasis aggravated with elevating serum GGT and TBIL lever. It plays the key role in warm ischemia injury of graft after liver transplantation that are MDA, ICAM-1, ET-1 and NO. The warm ischemia of graft heightened production of oxygen-derived free radicals. The warm ischemia injury of liver was aggravated with NO and ICAM-1 in the later stage of reperfusion. ET-1 could reflect the cold ischemia injure of graft in liver transplantation. ICAM-1 may be a good marker to indicate the degree ofhepatocyte injure.