Articular chondrocyte metabolism and osteoarthritis
The three main objectives of this study were: (1) to determine if depletion of proteoglycans from the cartilage matrix that occurs during osteoarthritis causes a measurable increase of cartilage proteoglycan components in the synovial fluid and sera, (2) to observe what effect intracellular cAMP has on the expression of matrix components by chondrocytes, and (3) to determine if freshly isolated chondrocytes contain detectable levels of mRNA for fibronectin. Canine serum keratan sulfate and hyaluronate were measured to determine if there was an elevation of these serum glycosaminoglycans in a canine model of osteoarthritis. A single intra-articular injection of chymopapain into a shoulder joint increased serum keratan sulfate 10 fold and hyaluronate less than 2 fold in 24 hours. Keratan sulfate concentrations in synovial fluids of dogs about one year old were unrelated to the presence of spontaneous cartilage degeneration in the joints. High keratan sulfate in synovial fluids correlated with higher keratan sulfate in serum. The mean keratan sulfate concentration in sera of older dogs with osteoarthritis was 37% higher than disease-free controls, but the difference between the groups was not statistically significant. Treatment of chondrocytes with 0.5 millimolar (mM) dibutyryl cAMP (DBcAMP) caused the cells to adopt a more rounded morphology. There was no difference between the amount of proteins synthesized by cultures treated with DBcAMP and controls. The amount of fibronectin (FN) in the media of DBcAMP treated cultures detected by an ELISA was specifically reduced, and the amount of {sup 35}S-FN purified by gelatin affinity chromatography decreased. Moreover, the percentage of FN containing the extra domain. A sequence was reduced. Concomitant with the decrease in FN there was an increase in the concentration of keratan sulfate.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States)
- OSTI ID:
- 5658342
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINES
AMP
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARTILAGE
CHROMATOGRAPHY
CONNECTIVE TISSUE
DAYS LIVING RADIOISOTOPES
DISEASES
DOGS
EVEN-ODD NUCLEI
GLYCOPROTEINS
HYALURONIC ACID
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MESSENGER-RNA
METABOLISM
MUCOPOLYSACCHARIDES
NUCLEI
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PATHOGENESIS
POLYSACCHARIDES
PROTEINS
RADIOISOTOPES
RHEUMATIC DISEASES
RNA
SACCHARIDES
SEPARATION PROCESSES
SKELETAL DISEASES
SULFATES
SULFUR 35
SULFUR COMPOUNDS
SULFUR ISOTOPES
TISSUES
TRACER TECHNIQUES
VERTEBRATES