Glucosamine Enhances Healing Rate

OBJECTIVES: To assess whether glucosamine (GlcN), an oral supplement commonly taken to relieve the symptoms of osteoarthritis, modulates the immune and inflammatory responses to joint injury in organs proximal to GlcN absorption; namely, the liver and the gut-draining lymph nodes.

METHOD: Using a papain-injected knee mouse model, standard histological methods were used to validate our model and document the impact of GlcN (100mg/kg/day) on groups of C57BL/6 mice (n=5). Circulating inflammatory cytokines were assessed by Luminex-based immunoassays and the relevance of this cytokine profile on proteoglycan biosynthesis evaluated using a patellar-cartilage assay. Real-time PCR was used to document the role of the liver in cytokine production. Finally, we appraised the activation of mesenteric lymph nodes (MLNs) lymphocytes by flow cytometry.

RESULTS: Papain significantly degraded the proteoglycans in the injected knees by 2 days. Cartilage proteoglycan content was significantly higher in GlcN-treated, papain-injected knees at Day 14. The peak concentration of serum pro-inflammatory cytokines occurred earlier and decreased sooner in the injected, GlcN-supplemented mice; this trend was in agreement with the expression of these factors by the liver. GlcN did not alter the percentage of MLN populations but accelerated their activation.

CONCLUSIONS: Oral GlcN alters the physiology of the liver and MLNs, which in turn, could indirectly alter the biology of the injured joint.