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Electron microscopic analysis of articular cartilage proteoglycan degradation by growth plate enzymes
Author(s) -
Buckwalter Joseph A.,
Ehrlich Michael G.,
Armstrong Ann L.,
Mankin Henry J.
Publication year - 1987
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.1100050116
Subject(s) - proteoglycan , monomer , cartilage , chemistry , chondroitin sulfate , chondrocyte , biophysics , articular cartilage , aggrecan , enzyme , glycosaminoglycan , keratan sulfate , biochemistry , polymer , osteoarthritis , anatomy , biology , extracellular matrix , in vitro , organic chemistry , medicine , alternative medicine , pathology
To assess the effect of intracellular growth plate chondrocyte enzymes on proteoglycan structure, we examined enzyme‐treated articular cartilage proteoglycans and untreated articular cartilage proteoglycans with the electron microscopic monolayer technique. The untreated proteoglycan monomers ranged in length from less than 20 nm to more than 700 nm, with a mean length of 224.5 + 101.6 nm in one experiment and 224.6 + 95.7 nm in a second experiment. Incubation with growth plate enzymes reduced proteoglycan monomers to fragments with lengths that varied from less than 5 nm to 143 nm, increased the variability in monomer length, and destroyed proteoglycan aggregates. The enzyme treated monomers had an average length of 29.5 + 17.9 nm in one experiment and 35.2 + 17.0 nm in a second experiment. The smallest common fragments were 15 nm long and would be expected to contain about 15 glycosaminoglycan chains. This experiment demonstrates that enzymes extracted from growth plate chondrocytes can degrade the chondroitin sulfate‐rich region of proteoglycan monomer core proteins, produce a range of monomer fragment sizes with less than 20% of the fragments shorter than 5 nm or longer than 100 nm, increase the variability in monomer length, and degrade proteoglycan aggregates.