DOES LEVEL OF LIGATION INFLUENCE RESULTS IN A MURINE BILIARY OBSTRUCTION MODEL

BACKGROUND: Despite advances in perioperative management, patients wit h extrahepatic biliary obstruction still experience a high rate of com plications and death after surgery. The rat is commonly used as an exp erimental animal for research in obstructive jaundice. Ligation of the rat bile duct high in the liver hilum is assumed to produce a more se vere model of biliary obstruction than low ligation. The differences a re attributed to the ability of the rat bile duct to dilate. Differenc es in level of ligation may, thus, explain some discrepancies between studies. MATERIALS AND METHODS: TO test this hypothesis, female Lewis rats underwent high ligation (HL), low ligation (LL), and sham celioto my. Colloidal carbon clearance, bilirubin, total serum bile acids, and hematocrit were measured 12 days later. Liver and spleen weight, pres ence or absence of ascites, infection, and adequacy of ligation were n oted and the liver was processed for routine histology and electron mi croscopy. RESULTS: Although bilirubin levels were higher after HL than after LL, liver and spleen weight, total serum bile salts, and phagoc ytic constants K and alpha were not different between these two groups . Gross, histologic, and ultrastructural appearance did not differ bet ween HL and LL groups. CONCLUSIONS: High ligation causes greater hyper -bilirubinemia than low ligation, but does not alter other parameters including phagocytic constants. The present study does not confirm the hypothesis that HL creates a more severe model than LL; therefore, it is unlikely that differences in level of ligation explain variability in results between studies.