Antiinflammatory effect of lactic acid bacteria: inhibition of cyclooxygenase-2 by suppressing nuclear factor-kappaB in Raw264.7 macrophage cells.

Lactobacillus casei 3260 (L. casei 3260) was evaluated in relation to the inflammatory response mediated by lipopolysaccharide (LPS)-induced nuclear factor-kappaB (NF-kappaB) and cyclooxygenase-2 (COX-2) expression in Raw264.7 macrophage cells. The treatment of Raw264.7 cells with L. casei 3260 significantly inhibited the secretion of tumor necrosis factor-alpha (TNF-alpha) and prostaglandins E2 (PGE2), followed by suppression of COX-2. To clarify the molecular mechanism, the inhibitory effect of L. casei 3260 on the NF-kappaB signaling pathway was examined based on the luciferase reporter activity. Although the treatment of Raw264.7 cells with L. casei 3260 did not affect the transcriptional activity of NF-kappaB, it did inhibit NF-kappaB activation, as determined by the cytosolic p65 release and degradation of I-kappaBalpha. Therefore, these findings suggest that the suppression of COX-2 through inhibiting the NF-kappaB activation by LPS may be associated with the antiinflammatory effects of L. casei 3260 on Raw264.7 cells.