Chondroitin

Mixtures of glucosamine and chondroitin sulfate reverse fibronectin fragment mediated damage to cartilage more effectively than either agent alone.

Homandberg GA, Guo D, Ray LM, Ding L.

Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Box 9037, Grand Forks, ND 58202, USA.

OBJECTIVE: To test the effectiveness of glucosamine (GluNH(2))-HCl, chondroitin sulfate (CS) and mixtures in protecting cartilage exposed to fibronectin fragments (Fn-fs), an exposure known to enhance catabolic cytokines and matrix metalloproteinases (MMPs). METHODS: Pharmacologic formulations of GluNH(2) (FCHG49((R))) and CS (TRH122((R))) (Nutramax Laboratories, Inc.) were added at 1, 10 or 100mug/ml singly or in mixtures to bovine cartilage cultures in serum or serum-free conditions with or without Fn-f. Proteoglycan (PG) release into media and remaining cartilage PG content were measured by dye binding analysis and effects on PG synthesis by assays of 35-sulfate incorporation. Effects on MMP-3 and -13 expression were measured by Western blotting of conditioned media. RESULTS: In serum-free conditions, the agents singly or as mixtures did not block Fn-f mediated matrix degradation. In serum, single agents were weakly effective at 100mug/ml, while the mixture of each agent at 0.1mug/ml decreased PG loss by about 50% by day 7 and at 1mug/ml restored nearly 50% of the PG after 7 days in Fn-f pretreated cartilage. However, both agents singly and as mixtures at 0.1-100mug/ml decreased MMP release. In serum, the single agents at 1-10mug/ml weakly reversed Fn-f mediated PG synthesis suppression, while the mixtures were 100% effective at 1mug/ml. CONCLUSIONS: GluNH(2) and CS act synergistically in reversing damage and promoting repair at concentrations found in plasma after oral ingestion of these agents. Reversal of PG synthesis suppression correlates more with these activities than suppression of MMP-3 or -13 expression.

PMID: 16581272 [PubMed - as supplied by publisher]