Semiquantitative reverse transcription-polymerase chain reaction analysis of syndecan-1 and-4 messages in cartilage and cultured chondrocytes from osteoarthritic joints

Objective: To determine the steady-state of messenger RNA (mRNA) levels of syndecan-1 and syndecan-4 in cartilage samples and chondrocytes derived fro m human osteoarthritic knee joints. Methods: Steady-state levels of gene-specific mRNA (relative to beta-actin) were measured-by semiquantitative polymerase chain reaction (PCR). Results:RT-PCR allowed detection of syndecan-1 (for the first time) and syn decan-4 in both cartilage samples and articular chondrocytes cultured as pr imary monolayers. The mRNA levels of syndecan-1 were reduced in cartilage t issue from heavily damaged compared to normal-looking areas whereas those o f syndecan-4 were significantly increased. In contrast, the expression of s yndecan-1 was higher in cultured chondrocytes derived from the fibrillated osteoarthritic cartilage than in cells obtained from intact cartilage, whil e the syndecan-4 message levels did not differ between the two sites. Conclusion: The expression of the cell-surface syndecans 1 and 4 is altered during the osteoarthritic degradative process of the knee joint. The disco ordinate syndecan gene expression, which is probably related to the chondro cyte proliferation and clustering, may contribute to the disorganization of the cartilage and the development of OA processes; isolation and culturing the chondrocytes as monolayers dramatically change the expression of these genes and cannot reflect the in situ condition. (C) 2000 OsteoArthritis Re search Society International.