Differential effects of bone associated factors on newly synthesized anionic glycoconjugates by articular chondrocyte cultures from adult and immature bovines.
OBJECTIVE
To determine if bone associated peptide factors (BAF) differentially affect proteoglycan and hyaluronic acid (HA) synthesis as a result of the maturity of the animal and of the location of chondrocytes within cartilage zones.


METHODS
Calf and adult bovine articular chondrocytes were isolated and cultured, as high density monolayers, with 3H-glucosamine and 35S-sulfate. The effects of commercial transforming growth factor beta (TGF-beta) and a preparation from bovine bone that contained the total extractable stimulatory activity for glycosaminoglycan (GAG) synthesis (matrigenin activity) were studied.


RESULTS
Calf chondrocytes spontaneously synthesized a higher proportion of proteoglycans of larger hydrodynamic size, but the addition of the BAF resulted in a proportionally greater shift in the adult chondrocytes towards the synthesis of larger proteoglycans, appearing in the medium. Subpopulations of adult chondrocytes from the deep zone synthesized spontaneously more chondroitin sulfate (CS) and less HA than chondrocytes from the superficial zone, but the calf chondrocytes from the 3 zones showed similar patterns of GAG synthesis. Adult chondrocytes from the deep zone had large responses to the BAF for HA but not CS synthesis, resembling the subpopulations of the calf chondrocytes.


CONCLUSIONS
BAF differentially modulate HA and CS synthesis of articular chondrocytes as a result of maturation and topography. We speculate as to how this differential response to BAF may help set the stage for the progression of osteoarthritis in weight bearing joints.
Howard
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Department of Medicine, Queen's University, Kingston, ON, Canada.
Anastassiades
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D000375:Aging / Q000378:metabolism*; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000378:metabolism; D002850:Chromatography, Gel; D004305:Dose-Response Relationship, Drug; D005944:Glucosamine / Q000378:metabolism; D006001:Glycoconjugates / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D013462:Sulfur Radioisotopes; D014020:Tissue Extracts / Q000494:pharmacology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014316:Tritium
D006001:Glycoconjugates; D013431:Sulfates; D013462:Sulfur Radioisotopes; D014020:Tissue Extracts; D016212:Transforming Growth Factor beta; D014316:Tritium; C054630:matrigenin; D006820:Hyaluronic Acid; D002809:Chondroitin Sulfates; D005944:Glucosamine