ALTERATIONS IN BILE-DUCTS AND PERIBILIARY MICROCIRCULATION IN RATS AFTER COMMON BILE-DUCT LIGATION

The chronological changes in ductular epithelium and peribiliary capil lary plexuses (PBPs) after bite duct ligation are not well understood. Therefore, we examined alterations in both intrahepatic bile ductules and peribiliary microcirculation in rats after ligation of the common bile duct using immunohistochemistry, transmission electron microscop es (TEM), and scanning electron microscopes (SEM). Ductular proliferat ions appeared first in the peripheral areas of the portal spaces and t he II gradually advanced along with increasing jaundice. Distorted con figuration of the hepatic parenchyma with interconnecting stroma rich in irregular ductules developed 4 weeks after the ligation. Numerous b iliary cell types and cells of types intermediate between hepatocytes and biliary cells together with poorly fenestrated. capillary-type ves sels appeared in the periportal parenchyma, in association with an inc reased number of canalicular-ductular junctions on TEM. These biliary cells were often found within the lobules and apart from the stroma. S EM examination of hepatic microvascular casts using methacrylated resi n showed formation of irregular portal and periportal capillary networ ks, partly derived from coarsened sinusoids. Direct connections betwee n the newly formed capillary networks and the pre-existing PBPs or sin usoids were numerous, although there were few direct connections betwe en the capillary networks and the hepatic arterial branches. Thus, the se proliferated ductules and newly formed complicated capillary networ ks might play an important role in the effective transport of biliary materials be. tween hepatocytes and native bile ducts or proliferated ductules through the altered microcirculation after bile duct ligation .