title: Proteoglycan alterations in rabbit knee articular cartilage following physical exercise and immobilization.
abstract: Rabbit knee articular cartilage was studied after the joint was submitted to immobilization, running or increased weight bearing for 24-27 days. Immobilization with a plastic splint reduced the fraction of proteoglycans not extractable with 4 M guanidinium chloride (GdnHCl). In the immobilized joints the chondroitin sulfate content was elevated as calculated from the galactosamine/glucosamine ratio. The ability of these proteoglycans to reform aggregates with endogenous hyaluronic acid in Sepharose CL-2B chromatography was reduced. Increased exercise was associated with an elevation of proteoglycans extractable with 4 M GdnHCl. The increased weight bearing occurring in the contralateral knee elevated the content of proteoglycans not extractable with 4 M GdnHCl. Other effects of weight bearing included increased glucosamine concentration, suggesting accumulation of keratan sulfate-rich proteoglycans, and an elevated hydroxyproline concentration.
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000032:analysis*; D002849:Chromatography, Gas; D002850:Chromatography, Gel; D005260:Female; D005688:Galactosamine / Q000032:analysis; D005944:Glucosamine / Q000032:analysis; D006595:Hexosamines / Q000032:analysis; D006868:Hydrolysis; D007103:Immobilization; D007719:Knee Joint; D008297:Male; D005082:Physical Exertion; D011509:Proteoglycans / Q000032:analysis*; D011817:Rabbits; D014461:Ultracentrifugation
chemical_list: D006595:Hexosamines; D011509:Proteoglycans; D005688:Galactosamine; D005944:Glucosamine