Vitamin K suppresses lipopolysaccharide-induced inflammation in the rat

Vitamin K (K) is essential for blood coagulation and bone metabolism in mammals. K acts as a cofactor in the posttranslational synthesis of γ-carboxyglutamic acid from glutamic acid residues. In addition to the liver and bone, K is found in the brain, heart, kidney and gonadal tissue. However, the physiological role of K in these various organs is not yet fully understood. It is likely that K has functions other than its role as a cofactor of protein γ-glutamyl carboxylation. We used in this study the DNA microarray technique to identify the effect of K status on gene expression in the rat liver. The expression of genes involved in the acute inflammation response was enhanced in rats fed with a K-deficient diet relative to the control and K₁-supplemented diet groups. Moreover, dietary supplementation with K₁ suppressed the inflammation induced by lipopolysaccharide administration. These results indicate that orally administrated K₁ suppressed inflammation in the rat.