Synthesis of articular cartilage proteoglycans by isolated bovine chondrocytes. Effect of autogenous conditioned synovial mediumin vitro

Abstract

It was previously reported that bovine conditioned synovial medium (SM) has a catabolic activity on articular cartilage proteoglycans in an organ culture system. The question thus arose whether SM had an anabolic effect as well on articular cartilage proteoglycans. In this report it is shown that addition of autogenous SM to isolated bovine articular chondrocytes inhibited the synthesis of proteoglycans as measured by the incorporation of radiosulphate. Already after 4 hours an inhibition was seen in the pericellular (matrix) chondroitin sulphate (MA-CS) fraction, and in the culture medium chondroitin sulphate (CM-CS) fraction it was significant after 72 hours. When the synovial tissue was cultured with indomethacin (1.4 X 10(-5) mol/l) and this indo-SM was added to the chondrocyte cultures, the ability of the chondrocytes to incorporate [35S]sulphate was decreased further. It therefore seems evident that the products from the synovial tissue influences the behaviour of the chondrocyte in such a way that not only is the degradation enhanced but also the synthesis of cartilage proteoglycans is inhibited.

Human synovium produces substances that inhibit DNA and stimulate proteoglycan and collagen synthesis by cultured human articular chondrocytes and synovial fibroblasts

“…In yet another study synovial fluid or culture media from synovial fluid cells of patients with juvenile RA strongly stimulated proliferation of normal human synovial fibroblasts (29). In contrast to our findings are those of two other groups who showed that SCM derived from human OA or rheumatoid synovial membranes induced inhibition more frequently than stimulation (14) or consistently inhibition of GAG synthesis by organ cultured bovine femoral condylar cartilage fragments (13) or isolated cells (30). These discrepancies could be due to different experimental protocols, particularly with respect to the controls (serum or serum-free medium) used in the cited studies and/or traduce species differences.…”

The Ultrastructure of Articular Cartilage in the Prenatal Pig

“…Most probably the final arrangement of chondroblasts during the development involves the two factors which, according to their respective involvement, characteristically affect the course and arrangement of fibres and fibrils in the intercellular matter. This is, together with the amorphous substance, responsible for mechanical properties of the articular cartilage, while the chondroblasts playa key role in manufacturing and maintaining the matrix (Balazs et al 1966;Imura 1984;Klamfeldt 1984). The literature data (Haines 1933;Levene 1964;Browerand Hsu 1969;Lufti 1970;Stockwell 1971;Wolf 1975;Kinca·id and Lindwalll982;Agraval et al 1984) as well as our observations involving cattle (Horky 1986) show the presence of blood vessels in the articular cartilage in the course of its development.…”