Visfatin regulates the production of lipopolysaccharide-induced inflammatory cytokines through p38 signaling in murine macrophages

Visfatin plays an important role in regulation of inflammatory cytokines. However, the role of visfatin under bacterial stress condition is not fully explored yet. Therefore, the present study was conducted for the better understanding of the regulation mechanism of visfatin on the production of inflammatory cytokines under lipopolysaccharide (LPS) stress in RAW264.7 murine macrophages. Enzyme Linked Immuno-sorbent Assay (ELISA) results showed that, as compared to the control group, visfatin significantly up-regulated the levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α (P < 0.05). Compared to the LPS group, the levels of IL-1β, IL-10, TNF-α was down-regulated in visfatin + LPS group (P < 0.05). After adding p38 inhibitor, SB203580 to culture, the production of IL-1β, IL-6, IL-10, TNF-α was significantly reduced as compared to visfatin only (P < 0.01). The results showed that visfatin may regulate the production of IL-1β, IL-6, IL-10, TNF-α through the p38 signaling pathway. As compared to the PBS group, phosphorylayed p38 (P-p38) level in visfatin group was significantly decreased (P < 0.05). Compared with LPS group, P-p38 level was significantly decreased in visfatin + LPS group (P < 0.05). Hence, it is concluded that visfatin can significantly increase the levels of IL-1β, IL-10 and TNF-α in normal conditions, while their levels significantly decrease during inflammation. Moreover, visfatin participates in the inflammatory response through the p38 mitogen-activated protein kinase (MAPK) signal pathway by the up-regulation of p38 and down-regulation of P-p38 levels.