ABSTRACT
The mature hyaline cartilage tissue is characterized by predominance of the extracellular matrix over the cells. Most of the cartilage matrix macromolecules are complexes of carbohydrates and proteins. There are three major classes of the cartilage matrix constituents: collagens; proteoglycans and glycosaminoglycans; and noncollagenous glycoproteins. This chapter distinguishes cell-surface associated, fibrillar, perifibrillar, and interfibrillar components. Due to the high frequency of degenerative and inflammatory joint diseases in human medicine, much effort has been directed towards a detailed understanding of the structure, composition, molecular anatomy, and function of the cartilage matrix. The most abundant type of proteoglycan (PG) in normal and differentiated hyaline cartilage matrix is the large aggregating PG. The fine structure of the cartilage matrix has been intensively studied both with electron microscope and polarization optics. The cartilage matrix is a heterogeneous system, in which microscopic and submicroscopic compartments can be distinguished.
