Perivascular connective tissue sheath and portal tracts in mammals

Abstract

Introduction: Many hepatic pathologies associated with the ductular reaction, changes of biliary mucosal glands, inflammation with leukocyte infiltration, etc. involve the liver portal tracts. The number of investigations indicates the role of portal tracts in the liver regeneration, innervation of the hepatic parenchyma; also, the portal tracts are important for surgeries aiming to treat the biliary atresia or conduct the liver graft transplantation.

To clarify the role of the portal tracts in development of various hepatic disorders, as well as successful implementation new interventions using the elements of a portal complex, requires translational investigations in different animals and therefore the studies of their portal tracts architecture for this purpose.

Method:We studied the architecture of the portal tracts of humans, canines and ratswith the following comparative analysis. The methods of macerating preparations,corrosion casts of tubular structures, histology (histotopography, histochemistry, immunohistochemistry) were used.

Conclusion: It was revealed that the overall architecture of the human, dog and rat portal tracts and the location of the elements in them is alike: the portal veins are surrounded by arteries and bile ducts, which are localized more peripherally – bordering liver parenchyma. However, in the animals the arterial-fibrous and biliary fibrous layers, which are the typical structures in humans, are less clearly developed.Humans’ and dogs’ bile ducts are supplied with mucous glands, while in rats, these structures are replaced by a periportal biliary plexus. This factshould be related to the absence of gallbladder and therefore, to the different conditions of bile drainage.