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Extracellular matrix alterations during endochondral ossification in humans
Author(s) -
Horton William A.,
Machado Mirta M.
Publication year - 1988
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100060603
Subject(s) - cartilage , extracellular matrix , fibronectin , endochondral ossification , microbiology and biotechnology , chemistry , aggrecan , type ii collagen , chondroitin sulfate , collagen, type i, alpha 1 , keratan sulfate , chondroitin sulfate proteoglycan , matrix (chemical analysis) , ossification , anatomy , type i collagen , proteoglycan , pathology , biology , glycosaminoglycan , biochemistry , endocrinology , osteoarthritis , medicine , articular cartilage , alternative medicine , chromatography
Immunohistochemical methods were employed to examine alterations in the cartilage extracellular matrix constituents associated with endochondral ossification in humans. The distributions of chondroitin 4‐ and 6‐ sulfate and keratan sulfate proteoglycan (PG) determinants. cartilage PG link protein. collagen types I and II. and fibronectin were determined in iliac crest growth‐plate specimens using the avidin‐biotin‐horseradish peroxidase system. Collagen type II was distributed throughout the growth plate, providing a framework within which chondrocytes divided and formed clusters of differentiating (hypertrophic) cells. The septa between these clusters and their subchondral extensions into underlying bone trabeculae were rich in PG. PG link protein, and collagen type II and resembled the extracellular matrix of reserve cartilage. The territorial matrix associated with the differentiating cells within the clusters contained reduced amounts of collagen type II, PG link protein, and possibly cartilage PG. Collagen type I and fibronectin were detected within the cytoplasm of the maturing and degenerating cells, and fibronectin localized intensely to the pericellular matrix envelopes of these cells. These alterations presumably facilitate the degradation of the matrix associated with the cell clusters by invading vascular tissue, while the septa. which retain the characteristics of more typical cartilage matrix, are not degraded and firmly anchor the cartilage to the subchondral bone.