Glycosaminoglycan metabolism in experimental osteoarthrosis caused by immobilization

A study was made of glycosaminoglycan metabolism of articular cartilage in developing experimental osteoarthrosis caused by immobilization of the rabbit knee. Cartilage samples from various sites in the knee and hip joints were analysed, samples from the mobile limb serving as controls. The concentration of glycosaminoglycans in the tissue was measured by determinations of hexosamine and uronic acid after prior papain proteolysis and subsequent purification. The uptake of 35S-sulphate was used as an indicator of the synthesis rate of sulphated glycosaminoglycans. Metabolic changes characteristic of osteoarthrosis, i.e., glycosaminoglycan depletion and increased uptake of 35S-sulphate, were found in tibial weight-bearing and femoral condylar cartilages. Net synthesis of glycosaminoglycans occurred in the tibial marginal cartilage.