The effects of glucosamine derivatives on equine articular cartilage degradation in explant culture

Objective: To determine whether glucosamine-3-sulfate, glucose-3-sulfate (c ontrol) and N-acetyl glucosamine inhibit experimentally induced degradation of equine articular cartilage explants similar to glucosamine HCl. Design: Articular cartilage was obtained from the antebrachio-carpal and mi ddle joints of horses (2-8 years old) killed for reasons unrelated to lamen ess. Cartilage discs were harvested from the weight-bearing region of the a rticular surface and cultured. Media were exchanged daily and the recovered media stored at 4 degreesC. On days 1 and 2 lipopolysaccharide (LPS, 10 mu g/ml) was added to induce cartilage degradation. To evaluate the effects of different sources of glucosamine ton an equal molar basis), varying concen trations of glucosamine HCl (0.25, 2.5, or 25 mg/ml), glucosamine-3-sulfate (0.304, 3.04, or 30.4 mg/ml), or N-acetyl-glucosamine (0.256, 2.56, or 25. 6 mg/ml) were added to the cultures. The glucose-3-sulfate control was adde d at 0.3075, 3.075 or 30.75 mg/ml. Nitric oxide and proteoglycan released i nto conditioned media and tissue proteoglycan synthesis and total tissue PG content were measured as indicators of cartilage metabolism. Results: Glucosamine-3-sulfate consistently inhibited cartilage degradation in a manner similar to glucosamine HCl, while the effects of N-acetyl-gluc osamine were highly variable and did not inhibit cartilage degradation. Glu cose-3-sulfate did not inhibit cartilage degradation. Conclusion: Our results indicate that glucosamine sulfate also has the pote ntial to prevent or reduce articular cartilage degradation similar to gluco samine HCl in vitro. The amine group at the carbon-2 position appears impor tant for the effectiveness of the glucosamine derivative. The therapeutic v alue of N-acetyl-glucosamine remains questionable. (C) 2000 OsteoArthritis Research Society International.