The inhibitory action of butyrate on lipopolysaccharide-induced nitric oxide production in RAW 264.7 murine macrophage cells

The effect of butyrate, a natural bacterial product of colonic bacterial fl ora, on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RA W 264.7 murine macrophage cells was studied. Butyrate significantly reduced NO production in LPS-stimulated RAW cells. The inhibition was abolished by the removal of butyrate. Butyrate also inhibited the expression of inducib le type NO synthase (iNOS) in LPS-stimulated RAW cells. Furthermore, butyra te prevented the activation of nuclear factor (NF)-kappa B through the stab ilization of I kappa B-alpha and I kappa B-beta. Butyrate did not affect th e phosphorylation of mitogen-activated protein (MAP) kinases by LPS. It was , therefore, suggested that butyrate down-regulated LPS-induced NO producti on in RAW cells through preventing the expression of iNOS, and that it was due to the inhibitory action of butyrate on the activation of NF-kappa B.