Premium
Slippery when wet: The free surface of the articular cartilage
Author(s) -
Raspanti Mario,
Protasoni Marina,
Zecca Piero Antonio,
Reguzzoni Marcella
Publication year - 2021
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.23684
Subject(s) - reticular connective tissue , articular cartilage , shearing (physics) , scanning electron microscope , cartilage , anatomy , materials science , glycosaminoglycan , composite material , ultimate tensile strength , biomedical engineering , biophysics , chemistry , osteoarthritis , pathology , biology , medicine , alternative medicine
The free surface of the articular cartilage must withstand compressive and shearing forces, maintain a low friction coefficient and allow oxygen and metabolites to reach the underlying matrix. In many ways it is critical to the physiology of the whole tissue and its disruption always involves deep pathological alterations and loss of the joint integrity. Being very difficult to image with section‐based conventional techniques, it was often described by previous research in conflicting terms or entirely overlooked. High‐magnification face‐on observations with high resolution scanning electron microscopy and with scanning probe microscopy revealed a very thin, delicate superficial layer rich in glycoconjugates, which may explain the very low friction coefficient of the tissue but which was very easily altered and/or dissolved in the preparation. Beneath this superficial sheet lies a thicker coat of thin, highly uniform, slightly wavy collagen fibrils lying parallel to the surface and mutually interconnected by a huge number of interfibrillar glycosaminoglycan bridges. These bridges and the collagen fibrils form an extended reticular structure able to redistribute tensile and compressive stress across a larger area of the surface and hence a greater volume of tissue.