Expression of glycoconjugates during intrahepatic bile duct development in the rat: an immunohistochemical and lectin-histochemical study.

We investigated the expression of carbohydrate residues on the developing intrahepatic bile ducts of rats. At 17 days of gestation, immature biliary cells around the portal vein close to the hepatic hilum assumed one of the following forms: slitlike lumen, incomplete, or complete bile ductule-like structures. These immature biliary elements then rapidly spread throughout the liver along with development. At birth, a few mature interlobular bile ducts became visible in the portal tracts. The cytoplasm of immature biliary cells stained weakly for concanavalin A, Erythrina crista galli agglutinin, and Limax flavus agglutinin, whereas the luminal surface of immature biliary cells at 17 days of gestation was positive for lectins, similar to those that are expressed on the luminal surface of the mature bile ducts, including concanavalin A, succinyl wheat germ agglutinin, Vicia villosa agglutinin, soybean agglutinin, peanut agglutinin, Erythrina crista galli agglutinin, and Limax flavus agglutinin. As development progressed, the number of lectins binding to the cytoplasm of biliary cells gradually increased, and lectin bindings to the luminal surface of biliary cells gradually became intense. Immature biliary epithelial cells of three structures expressed similar carbohydrate residues in their cytoplasm and luminal surfaces. This study suggested that the profile of carbohydrate residues on the biliary epithelium changes with development. Therefore, this profile could be a useful tool with which to evaluate the development of the biliary tree as well as associated disorders.