Abstract: Objective To investigate the effect of metformin on inflammatory cytokines of saturated fatty acid (SFA)-induced RAW264.7 macrophage. Methods RAW264.7 cells were treated with SFA to establish inflammatory model in vitro. Macrophages were divided into normal control group, SFA-treated group, metformin + SFA-treated group and AMPK inhibitor Compound C + metformin + SFA-treated group. Real-time quantitative PCR was used to detect mRNA expression levels of TNF-α and IL-6. ELISA was used to detect secretion levels of TNF-α and IL-6 in cell supernatants. Western blotting was used to analyze phosphorylation level of AMP-activated protein kinase. Results Compared to normal control group, both mRNA expression levels and protein secretion levels of TNF-α and IL-6 were elevated in SFA-treated group (P<0.05). Compared to SFA-treated group, both mRNA expression levels and protein secretion levels of TNF-α and IL-6 were decreased in metformin + SFA-treated group (P<0.05), and AMPK phosphorylation level was significantly enhanced (P<0.05). Compared to metformin + SFA treated-group, mRNA expression and protein secretion levels of TNF-α and IL-6 were elevated， and AMPK phosphorylation level was deceased in Compound C + metformin + SFA-treated group (P<0.05). Conclusion Metformin suppresses secretion of inflammatory cytokines TNF-α and IL-6 in saturated fatty acid-induced RAW264.7 macrophage via activation AMPK.

Key words: RAW264.7 macrophage, metformin, saturated fatty acid, AMP-activated protein kinase, inflammatory cytokine