[A histochemical study on the acidic glycoconjugates of the synovial membrane in rheumatoid arthritis]

The localization and the nature of glycosaminoglycans (GAGs) in the synovial membrane in 30 patients with rheumatoid arthritis (RA) involving 40 knees were studied by newly developed histochemical methods. To detect the acidic glycoconjugates, sensitized diamine procedures were employed based upon high and low iron diamine stainings. To identify the various molecular species of the GAGs, enzyme (chondroitinase ABC and B, testicular hyaluronidase and keratanase) digestion and chemical modification (nitrous acid treatment) procedures were performed prior to the diamine stainings. The sensitized diamine methods could clearly stain the acidic glycoconjugates contained in the synovial tissue components in shades of brown to black, and could detect the precise distribution patterns of the GAGs. The results obtained in the present study confirmed that the tissue in RA synovial membranes contained various amounts of each GAG molecular species such as dermatan sulfate, chondroitin sulfate A/C, hyaluronic acid and heparan sulfate. Furthermore, the distribution patterns of dermatan and chondroitin sulfates in the diseased synovial tissues were pathophysiologically interesting; in the inflammatory areas, the molecular species of GAGs was primarily dermatan sulfate, whereas in the fibrotic areas, it was mainly chondroitin sulfate A/C. Such results appear to be useful for pathophysiological studies on the synovial tissues of RA.