Three-dimensional organization of the collagen fibrillar framework of the human and rat livers

Abstract

The collagen fibrillar framework in the human and rat liver was demonstrated by a cell-maceration/scanning electron microscope (SEM) method. Maceration of fixed tissues with alkali plus water successfully removed the cellular elements, exposing collagen fibrils which measured about 60 nm in diameter and were identified as such by transmission electron microscopy (TEM). The normal human liver contained 12.4 mg of collagen fibrils/g of wet tissue, while rat livers contained 1.3 mg of collagen fibrils/g of wet tissue. In the Glisson's sheaths were condensations of collagen fibrils which extended to the hepatic lobules. In the spaces of Disse collagen fibrils ran either solitarily or in bundles and formed sheaths for housing the sinusoids. The central veins and the sublobular veins were also surrounded by the collagen fibrillar sheaths which were continuous with those in the spaces of Disse. Between adjacent sheaths of sinusoids frequently stretched collagen fibrillar bundles which were confirmed by TEM to occur in inter-hepatocellular spaces continuous with the spaces of Disse. The collagen fibrillar layer of the human liver capsule was much thicker (70-100 microns in thickness) than that of the rat liver (less than 5 microns in thickness). The collagen fibrils of the capsule were also continuous with those in the spaces of Disse. The collagen fibrillar framework of the liver is presumed not only to mechanically support the tissue, but also to form a microenvironment for hepatocytes and cells in the Disse's space.