Background Glucosamine sulfate is used for the management of osteoarthritis of the knee.
The mechanism of its effects needs clarification.
Objectives To evaluate the effects of glucosamine sulfate on the production of nitric oxide (NO) and stromelysin (MMP3) and cartilage synthesis in human osteoarthritic cartilage in the presence of IL-1b or LPS.
Methods Cartilage was obtained in the operation theatre from patients undergoing total knee replacement for osteoarthritis, cut into small pieces and cultured in the presence or absence of IL-1b or LPS.
NO in culture media was measured with the Griess reagent, MMP-3 by ELISA and cartilage synthesis by 35S incorporation.
Results IL-1b (1 ng/ml) and LPS (3μg/ml) stimulated NO release in human osteoarthritic cartilage cultures about four fold. Glucosamine sulfate (1μg/ml, 10μg/ml, 100μg/ml) inhibited stimulated NO production in a dose dependent manner, reaching statistical significance (p < 0.05) at 100μg/ml glucosamine sulfate (60% and 38% inhibition respectively).
Glucosamine sulfate (100μg/ml) significantly (p < 0.05) inhibited MMP-3 release in IL-1b and LPS stimulated cartilage cultures. IL-1b and LPS inhibited cartilage synthesis by 70% and 50% respectively (p < 0.001). Glucosamine sulfate reversed this inhibition in a dose dependent manner reaching statistical significance (p < 0.05) at 10μg/ml glucosamine sulfate.
Conclusion Glucosamine sulfate may protect human osteoarthritic articular cartilage by inhibiting local NO and MMP-3 production and by reversing IL-1b inhibition of cartilage synthesis.