INHIBITORY EFFECTS OF GLUCOSAMINE ON LIPOPOLYSACCHARIDE-INDUCED ACTIVATION IN MICROGLIAL CELLS

Abstract

SUMMARY

1. The aim of the present study was to investigate the effects of glucosamine on lipopolysaccharide (LPS)-induced cellular activation in microglia and to evaluate the inhibitory mechanisms involved. 2. Lipopolysaccharide (100 ng/mL) was used for the activation of primary cultured rat microglial or BV2 microglial cells. Changes in intracellular Ca

2+

levels and outward K

+

currents were measured using fura-2/AM and whole-cell patch-clamp methods, respectively. Lipopolysaccharide- induced expression of tumour necrosis factor (TNF)-



mRNA was analysed by reverse transcription–polymerase chain reaction. 3. Lipopolysaccharide transformed cell morphology into an amoeboid shape

in

vitro

and induced microglial activation

in vivo

, as measured by immunohistochemical staining, but glucosamine inhibited this activation. Glucosamine also inhibited LPS-induced Ca

2+

influx, outward K

+

currents and TNF-



mRNA expression, which are typically representative of microglial activation. 4. The results suggest that the inhibitory mechanisms of glucosamine on LPS-induced microglial activation include inhibition of Ca

2+

influx and outward K

+

currents, as well as downregulation of the microglial activator gene TNF-



. Key words: glucosamine, lipopolysaccharide, microglial activation.