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

The proteoglycans chondroitin-4-sulphate/dermatan sulphate (Ch4S/DS) and chondroitin-6-sulphate (Ch6S) may have distinct functions in normal and diseased synovium. Proteoglycans are found in connective tissue and act as binding material. Ch4S/DS and Ch6S are structurally identical but are found in different parts of synovial tissue. The synovium is a membrane which excretes a transparent fluid in joint cavities and tendons. Researchers examined synovial samples from four patients with osteoarthritis (OA), 10 patients with rheumatoid arthritis and six healthy subjects (control group). OA and RA are both joint diseases. Ch4S/DS was distributed throughout all synovial tissues and was found on blood vessels of RA samples. Ch6S was found in the lining layer of normal synovium but was absent from this site in both diseased samples. Ch6S was present on the blood vessels of all tissue samples.