Electron Microscopic Observation on the Localization of Acid Mucopolysaccharides in Collagen Fiber Formation and Resorption in Experimental Hepatic Fibrosis

Abstract

The topographic relationship between collagen fibrils and acid mucopolysaccharides (AMPS) has been disclosed to a certain extent since the introduction of ruthenium red stain, which had been used by botanists to demonstrate pectic substance in plant cell walls, into the field of electron microscopy. Not many works, however, have been reported on this subject, and practically no papers are encountered dealing with the ultrastructure of AMPS in collagen fiber formation and resorption in hepatic fibrosis.
AMPS is noted as amorphous substance inbetween collagen fibrils and filaments. It is also observed as amorphous coat surrounding immature collagen fibrils. In areas it is observed as granules within the collagen filaments.
Ruthenium red positive granules around 100 Å in diameter are placed fairly regularly on the surface of the mature collagen fibrils at the intervals around 640 Å. In some portion of the collagen fibrils ruthenium red positive material is noted as cross striation corresponding to the cross striation of mature collagen fibrils.
These ruthenium red positive granules are absent in the degraded collagen fibrils. AMPS appears to be phagocytosed by macrophages in the resorption of collagen fibers.