Etomidate Mitigates Lipopolysaccharide-Induced CD14 and TREM-1 Expression, NF-κB Activation, and Pro-inflammatory Cytokine Production in Rat Macrophages.

Abstract

This study was aimed at investigating the effect of etomidate on the viability of rat macrophages and the function of lipopolysaccharide (LPS)-stimulated macrophages as well as the potential mechanisms. Rat macrophages were isolated and treated with different doses of etomidate for 24h, and their viability was determined by the CCK-8 assay. Furthermore, macrophages were treated with, or without, 1μg/ml of LPS, and/or 2.5 or 5μM etomidate in the presence or absence of a TREM-1 inhibitor (LP17, 100ng/ml), and the levels of TNF-α, IL-6, CD14, and TREM-1 in the different groups of cells were determined by quantitative RT-PCR, ELISA, and Western blot assays. The levels of NF-κB activation in the different groups of cells were analyzed by an electrophoretic mobility shift assay (EMSA). Etomidate at 31.25μM or a low dose did not affect the viability of rat macrophages, while etomidate at higher doses reduced the viability of macrophages in vitro. Treatment with 2.5 or 5μM etomidate or with LP17 alone did not affect the levels of TNF-α, IL-6, CD-14, and TREM-1 in macrophages. Treatment with etomidate significantly mitigated LPS-stimulated TNF-α, IL-6, CD-14, and TREM-1 expression (p < 0.05 for all) and inhibited LPS-induced NF-κB activation in macrophages in vitro. However, treatment with both etomidate and LP17 did not enhance the inhibitory effects in macrophages. Hence, etomidate mitigates LPS-up-regulated pro-inflammatory cytokine production and inhibits LPS-enhanced CD14 and TREM-1 expression and NF-κB activation in macrophages.