title: Proteoglycan metabolism of equine articular chondrocytes cultured in alginate beads.
abstract: Equine chondrocytes were cultured in vitro for 30 days in ionically gelled alginate beads. The alginate polymerises into a stable gel in the presence of divalent cations (calcium), and rapid depolymerisation in the presence of a calcium chelator releases the viable chondrocytes. The chondrocytes maintained a spherical appearance for 30 days in culture, in marked contrast to monolayer cultures, which develop a dedifferentiated fibroblastic morphology. The major proteoglycan molecule produced by the encapsulated chondrocytes was aggrecan, of similar hydrodynamic size to aggrecan molecules present in the matrix of the articular cartilage from which the cells were harvested. Link protein, keratan sulphate and chondroitin sulphate were also synthesised by the chondrocytes, as demonstrated by immunohistochemistry. The proteoglycan secreted by the chondrocytes consisted of at least two pools, one remaining adjacent to the cell and forming a dense, cell-associated matrix, and another migrating more peripherally into the intercellular compartment. Newly synthesised proteoglycans extracted from the pericellular matrix and the intercellular matrix were similar in hydrodynamic size and aggregated in the presence of exogenous hyaluronan.
authors.affiliation: Royal Veterinary College, University of London, Hertfordshire.
authors.forename: D
authors.initials: D
authors.lastname: Platt
authors.forename: T
authors.initials: T
authors.lastname: Wells
authors.forename: M T
authors.initials: MT
authors.lastname: Bayliss
mesh_terms: D000464:Alginates; D000818:Animals; D001345:Autoradiography / Q000662:veterinary; D002118:Calcium / Q000494:pharmacology; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000378:metabolism; D006736:Horses / Q000378:metabolism*; D007150:Immunohistochemistry; D007632:Keratan Sulfate / Q000378:metabolism; D008863:Microspheres; D010641:Phenotype; D011509:Proteoglycans / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000464:Alginates; D011509:Proteoglycans; D002809:Chondroitin Sulfates; D007632:Keratan Sulfate; D002118:Calcium