Chitosan oligosaccharides suppress production of nitric oxide in lipopolysaccharide-induced N9 murine microglial cells in vitro

Chitosan oligosaccharides (COS) have been reported to exert many biological activities, such as antioxidant, antitumor and anti-inflammatory effects. In the present study, we examined the effect of COS on nitric oxide (NO) production in LPS induced N9 microglial cells. Pretreatment with COS (50 similar to 200 mu g/ml) could markedly inhibit NO production by suppressing inducible nitric oxide synthase (iNOS) expression in activated microglial cells. Signal transduction studies showed that COS remarkably inhibited LPS-induced phosphorylation of p38 MAPK and ERK1/2. COS pretreatment could also inhibit the activation of both nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1). In conclusion, our results suggest that COS could suppress the production of NO in LPS-induced N9 microglial cells, mediated by p38 MAPK and ERK1/2 pathways.