Normal rat liver cytochemistry: search for reactions adapted to the study of experimental cholestasis

Experimentally induced intrahepatic cholestasis is characterized by a profound change in biliary secretion. Although there is general agreement that the biliary pole of the hepatocyte undergoes a singular alteration, it is know to which extent the microfilament network of the pericanalicular ectoplasm, the actual hepatocytic membrane at the biliary pole, and the intracanalicular glycocalix covering the membrane are implicated in this change. In order to establish whether ultrastructural cytochemistry is a suitable approach to a selective analysis of these three constituents, we decided to study the liver of normal rats with three different types of reactions (based on tannic acid, ruthenium hexamine, and digitonin, respectively). Moreover, we used different variants of each reaction and tried to determine which of them produced the most selective results; at the same time we kept in mind that these procedures are to be compatible with certain requirements of biological experimentation, like continuous bile flow measurement. Our findings show that, for a more detailed analysis of each of the above mentioned three cell constituents, these methods may provide more precise information.