BILE SECRETORY FUNCTION OF THE ARTERIALIZED VERSUS NONARTERIALIZED RAT-LIVER ALLOGRAFT

Arterialized and nonarterialized rat models of orthotopic liver transp lantation are widely used for studying various aspects of graft functi on. Although bile duct damage has been implicated in graft nonarterial ization, any impact on graft secretory function is unknown. This study sought to investigate whether nonarterialized orthotopic liver transp lantation (NOLT) is a valid model for studying bile formation after th e animal has fully recovered from the perioperative period. Twenty-fou r-hour bile collections were performed on eight arterialized and eight nonarterialized rats 4 weeks after transplantation to avoid the confo unding effects of preservation-reperfusion injury and perioperative st ress. Eight unoperated rats were used as control. There was no differe nce in mortality or biliary complications between the two transplant g roups. The nonarterialized rats exhibited a higher serum aminotransfer ase level, but serum bilirubin was normal. NOLT resulted in more porta l lymphocytic infiltration and bile ductular proliferation. Despite th ese histologic changes, bile duct epithelial cells remained intact, an d spontaneous graft rearterialization was evident in the NOLT group. B ile salt secretion, pool size, and synthesis in both transplant groups did not differ from unoperated rats. NOLT did not adversely affect ei ther bile acid-dependent or bile acid-independent flow. Biliary choles terol secretion was markedly reduced in both transplant groups, result ing in a more favorable cholesterol saturation index. In conclusion, h epatic allograft secretory function is well maintained at 4 weeks even in the absence of hepatic arterial reanastomosis. Compensatory mechan isms possibly prevent irreversible hepatobiliary damage in NOLT. The N OLT model is quite reasonable to study bile formation after transplant ation.