Figure 2.

Effects of carboxybutyrylated glucosamine (CGlcN) on the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in RAW264.7 cells. (a) Cells cultured in phenol red and serum-free media were pretreated with different concentrations of CGlcN for 1 hr and stimulated with a 1-µg/ml final concentration of LPS for 48 hr. Conditioned medium was mixed with an equal amount of the Griess reagent and the absorbance, measured at 550 nm, represented the amount of (stable oxidation product of NO) in the medium. The values obtained were compared with those of standard concentrations of sodium nitrite dissolved in Dulbecco's modified Eagle's minimal essential medium (DMEM), and the concentrations of nitrite in conditioned media of sample-treated cells were calculated. (b) Cells growing in serum-free medium were pretreated with different concentrations of CGlcN for 1 hr and stimulated with LPS (1 µg/ml final concentration) for 24 hr. The amount of PGE₂ release was determined by the mouse PGE₂ enzyme-linked immunosorbent assay (ELISA) kit. BLK, LPS non-stimulated cells; LPS, LPS-stimulated cells. Statistical comparisons, *P < 0·05 and **P < 0·01.