Zonal distribution of chondroitin-4-sulphate/dermatan sulphate and chondroitin-6-sulphate in normal and diseased human synovium.

OBJECTIVES Chondroitin sulphate is the major sulphated glycosaminoglycan present in the extracellular matrix of soft connective tissues and the aim of this study was to investigate the distribution of chondroitin sulphate species in normal and diseased synovium. METHODS Distribution of chondroitin-4-sulphate/dermatan sulphate (Ch4S/DS) and chondroitin-6-sulphate in normal (n = 6), osteoarthritic (n = 4) and rheumatoid (n = 10) synovium was determined using an immunoperoxidase technique and specific monoclonal antibodies to chondroitinase ABC-digested preparations. RESULTS Ch4S/DS was expressed throughout the interstitium of all tissues and was also present on blood vessels in rheumatoid samples only. Ch6S was expressed in the lining layer of normal synovium but was absent from this site in osteoarthritic and rheumatoid tissues. Ch6S was also present on all blood vessels in all tissues. CONCLUSIONS The distinct zonal distributions of Ch4S/DS and Ch6S and their alteration in disease suggest these molecules have different and specific functions in normal and diseased synovium.