Suppression of pannus-like extension of synovial cells by lipid-derivatized chondroitin sulphate: in vitro and in vivo studies using Escherichia coli-induced arthritic rabbits.

In rheumatoid arthritis, pannus formation resulting from synovial inflammation is a major factor in cartilage destruction. The ability of arthritic synovial cells to undergo pannus formation depends upon their initial adhesion to the partially deformed cartilage surfaces. Our recent studies using various lipid-derivatized glycosaminoglycans have revealed a preeminent inhibitory activity of phosphatidyl ethanol amine-derivatized chondroitin sulphate (CS-PE) toward cell-matrix adhesion. Here we evaluate whether CS-PE may protect articular cartilage from pannus extension in different in vitro and in vivo model systems using Escherichia coli 0:14-induced arthritis in rabbits and the articular cartilage explants, synovial tissues, and synovial cells obtained from them. These studies showed that CS-PE suppressed the in vivo pannus-like extension on cartilage surfaces, as well as the in vitro extension of the synovial cell layer on both CS-PE treated culture plates and cartilage explants. The results suggest that native chondroitin sulphate proteoglycans in the surface of normal articular cartilage play an important role in protecting the tissues from pannus extension and that the CS-PE immobilized onto partially eroded cartilage can mimic the inhibitory action of native chondroitin sulphate proteoglycans.