Histologic Study on Reperfusion Liver after the Revascularization through the Portal Vein or Hepatic Artery Following Heterotopic Partial Liver Transplantation in Rats

Youn, Myung Hee; Lee, Chung Han; Han, Koon Taek; Kim, Dong Hun; Sim, Mun Sup

Abstract

PURPOSE: The technique of partial liver transplantation from a living donor was developed to expand the donor pool. However such small grafts may not only be functionally inadequate for the recipient, but will also sustain injury characterized by cholestasis and histological features of ischemia after implantation. Damage to partial liver grafts after reperfusion is frequently observed but the mechanism of injury remains unclear. Injury to partial liver grafts may be related to changes in portal blood flow. In this study, we investigated the histologic changes of the reperfusion of livers after revascularization through the portal vein or hepatic artery following heterotopic partial liver transplantation in rats.
METHODS
Inbred Lewis partial liver were transplanted to inbred Brown Norway rats heterotopically in three groups. The first group of transplants, Group I (Portal vein group, n=3) was reperfused firstly through the portal vein. The second group, Group II (Hepatic artery group, n=3) was firstly reperfused through the hepatic artery. The third group, Group III (Control, n=1) was sham-operated. After reperfusion, the liver grafts were procured and fixed in formalin. The reperfusion livers were studied using immunohistochemical staining and in-situ RT PCR.
RESULTS
In the H&E staining of the reperfusion livers there were no differences between groups I and II. Using immunohistochemical staining of TNF,R, FAS L, caspase 8 and in-situ RT PCR (NOS mRNA, TNF,R mRNA, FAS mRNA), the hepatic artery first reperfusion liver showed more damage than the portal vein first reperfusion liver. TUNEL staing showed severe apoptosis in hepatic artery reperfusion liver.
CONCLUSION
The expression of the apoptosis molecular markers was more prominent in the reperfused liver performed with initial revascularization using the hepatic artery, rather than portal vein. These findings may be due to fact that the high oxygen blood in the hepatic artery is stressful to the reperfusion liver. The routinely used portal vein first revascularization technique decrease reperfusion injury to the graft when compared to hepatic artery first revascularization.