Blumea balsamifera （L.） DC Oil Alleviates LPS-Induced Inflammatory Response in Macrophages by Affecting Arachidonic Acid Metabolism Via NF-κB Nonclassical Pathway / 中山大学学报(医学科学版)

ABSTRACT

ObjectiveTo study the anti-inflammatory effects of Blumea balsamifera （L.） DC oil （BBO） based on nuclear factor kappa-B （NF-κB） nonclassical and arachidonic acid （AA） pathway. MethodsEffects of BBO on the production of slow reacting substance of anaphylaxis （SRS-A） were detected by the ileal smooth muscle method. The contents of prostaglandin E2 （PGE2） and leukotriene B4 （LTB4） in lipopolysaccharides （LPS） -induced macrophages were detected by ELISA kit. The expression of COX-2， 5-LOX， FLAP and RelB were detected by qRT-PCR. Western blot was performed to detect the effects of BBO on the level of NF-κB nonclassical pathway proteins TNF receptor associated factor 3 （TRAF3）， TNF receptor associated factor 2 （TRAF2）， NF-κB-inducing kinase （NIK）， p100 and RelB. ResultsThe contractile tension of guinea pig ileum was reduced （P<0.001）， and the SRS-A production inhibition rate reached 65.34% at 1mg·mL-1 BBO concentration. Compared with LPS group， BBO reduced the concentrations of PGE2 （P<0.05） and LTB4 （P<0.05）， and decreased the expressions of COX-2 （P<0.05）， 5-LOX （P<0.05） and FLAP （P<0.05） in AA pathway at concentrations of 40-80 μg·mL-1. Moreover， 40-80 μg·mL-1 BBO decreased the concentrations of TRAF3 （P<0.05）， TRAF2 （P<0.05）， and NIK （P<0.05）， and further inhibited the phosphorylation of p100 （P<0.05）， as well as the level of the transcription factor RelB in genes （P<0.05） and proteins （P<0.05） in nonclassical NF-κB pathway， whereas BBO did not cause such changes. ConclusionBBO may potentially exert its anti-inflammatory effects by suppressing the regulatory proteins TRAF3 and TRAF2 and the transcription factor RelB in NF-κB nonclassical pathway. The inhibitory action extending to the induction kinase function of NIK， further hindering the phosphorylation of p100 and its binding with the transcription factor RelB. Consequently， downstream elements in the AA pathway， including the pivotal rate-limiting enzymes COX-2， 5-LOX and FLAP， were altered. This modulation influences the levels of inflammatory mediators such as PGE2 and LTB4.