Abstract
Articular cartilage taken from secondary osteoarthritic hip joints presented for surgical reconstruction was analyzed. Proteoglycans (PG) were isolated from the articular cartilage. Isolation of PG was done as described by Hascall and Sajdera (J Biol Chem, 244: 2384, 1969) . The aggregative PG were analyzed for chondroitin 4-sulfate (Ch-4S) and chondroitin 6-sulfate (Ch-6S) by physicochemical methods. Content of Ch-4S and Ch-6S in PG was analyzed by high performance liquid chromatography (HPLC) and the viscosity of PG monomer was analyzed by a Cannon-Manning semimicro viscometer. The relative viscosity (ηrel), specific viscosity (ηsp), and reduced viscosity (ηred) were calculated. Statistical analyse were performed. Pearson's correlation coefficient between parameters was calculated. The mathematical relationships between cartilage weight and reduced viscosity (ηred), between cartilage weight and Sum Ch.S, and between Sum Ch.S and Ch-6S/Ch-4S were calculated. There were significant correlations between these variables. The osteoarthritic femoral head PG molecules were smaller and the content of Sum Ch.S higher, for advanced osteoarthritis. The PG side chains were shorter and the number of chains per core-protein was higher, as the osteoarthritis was progressed. Changes in articular cartilage composition, proteoglycan molecular structure, and the ultrastructural arrangement of these macromolecules associated with osteoarthritis causes a deterioration in cartilage properties and hence a loss of functional capacity of the joint.
