Blueberries reduce pro-inflammatory cytokine TNF-α and IL-6 production in mouse macrophages by inhibiting NF-κB activation and the MAPK pathway

Abstract

Blueberries (BB) have been reported to attenuate atherosclerosis in apoE-deficient (ApoE(-/-) ) mice. The aim of this study was to evaluate the effects of BB in reducing pro-inflammatory cytokine production in mouse macrophages. ApoE(-/-) mice were fed AIN-93G diet (CD) or CD formulated to contain 1% freeze-dried BB for 5 wk. TNF-α and IL-6 were lower in serum of BB-fed mice and TNF-α expression in aorta was down-regulated with BB feeding. Protein level and mRNA expression of TNF-α and IL-6 were significantly lower in the peritoneal macrophages from mice fed BB without or with LPS or oxLDL stimulation. RAW264.7 macrophages were treated with polyphenol-enriched extracts made from the sera of rats fed CD (SEC) or CD containing 10% BB (SEB). SEB significantly inhibited LPS-induced mRNA expression and protein levels of TNF-α and IL-6. Furthermore, SEB inhibited the phosphorylation of IκB, NF-κB p65, MAPK p38 and JNK. All of these are important signaling pathways involved in the production of TNF-α and IL-6.