Suppression mechanisms of glucosamine on neutrophil functions
Isao NAGAOKA1, Jian HUA1, and Koji SAKAMOTO2
Abstract :Glucosamine, an amino monosaccharide occurring naturally in the connective and cartilage tissues, contribute to maintain the strength, flexibility and elasticity of these tissues. In recent years, glucosamine has been widely used to treat osteoarthrltis in humans. Neutrophils, which usually function as the primary defenders in acute bacterial infections, are also implicated in the destructive inflammatory responses in arthritis. In this study, we evaluated the actions of glucosamine on neutrophil functions, Glucosamine suppressed superoxide anion generation by neutrophils, and inhiblted phagocytosis of opsonized particles. Furthermore, glucosamine inhibited the release of granule enzyme from phagocytosing neutrophils, and repressed chemotaxis. In addition, glucosamine significantly inhibited the upregulation of adhesion mclecule CD11b, polymerization of actin and phosphorylation of p38 MAPK, associated with neutrophil activation. In contrast, N-acetyl-glucosamine, an analogue of glucosamine, did not affect these neutrophil functions. Together these observations likely suggest that glucosamine suppresses the neutrophil functions, thereby possibly exhibiting the anti-inflammatory actions in arthritis.