The effect of Condrosulf® (sodiumchondroitinsulfate) on total proteoglycan synthesis by human osteoarthritic and bovine juvenile articular chondrocytes -: an in vitro study

Background: Sodiumchondroitinsulfate, Condrosulf(R), is used in osteoarthritis therapy and belongs to the group of symptomatic slow-acting drugs for osteoarthritis. The aim of this study was to investigate the effects of Condrosulf(R) on total proteoglycan synthesis and cell proliferation in human osteoarthritis and healthy juvenile bovine chondrocytes in vitro. Methods: Chondrocytes were grown as monolayers and stimulated for 7 (human cartilage), or 4, 8 and 12 days (bovine cartilage) with different concentrations of Condrosulf(R) (100 mug/ml, 500 mug/ml, 1000 mug/ml, 2500 mug/ml and 5000 mug/ml). Proteoglycan synthesis was measured by [S-35]Sulfate incorporation. The cell proliferation rate was determined using a [H-3]Thymidin assay. The expression of the cartilage markers aggrecan and collagen type II was assessed by Northern blot analysis. Results: We show that the incubation with Condrosulf(R) did not affect proteoglycan synthesis neither in osteoarthritis, nor in healthy chondrocytes under the present culture conditions. Cell proliferation rate was also not increased by Condrosulf(R) stimulation. The results of the Northern blot assays demonstrated a dose-dependent down regulation of aggrecan expression on mRNA level. Conclusions: These data indicate a lack of direct anabolic effects of Condrosulf(R) on the biosynthetic activity of cultured articular chondrocytes. The well known ease of clinical symptoms, such as pain or swelling under Condrosulf(R) medication may be interpreted by an interaction with pro-inflammatory cytokines.