Xiaojindan Extract Modulated Macrophage Polarization by Targeting PI3K/Akt Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the effect and mechanism of Xiaojindan extract （XJD） on macrophage polarization. MethodLipopolysaccharide （LPS） and interleukin-4 （IL-4） were used to induce M1 and M2 polarization of RAW264.7 cells. The influence of 10-80 mg·L-1 XJD on cell proliferation was detected by Cell Counting Kit-8 （CCK-8） assay. Nitric oxide （NO） and interleukin-6 （IL-6） release was explored by Griess assay and enzyme-linked immunosorbent assay （ELISA）， respectively. The mRNA expression of M1 and M2 macrophage markers was measured by real-time quantitative polymerase chain reaction （Real-time PCR）， and the CD206+ expression was determined by flow cytometry. The activation of phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt） pathway was analyzed by western blot. Result10-80 mg·L-1 XJD showed no marked cytotoxicity in LPS （0.5 mg·L-1）- or IL-4 （20 μg·L-1）-induced RAW264.7 cells. Compared with the control group， LPS significantly promoted the expression of M1 macrophage markers （P<0.01）， including increased NO and IL-6 release （P<0.01） and upregulated mRNA expression of interleukin-1β （IL-1β）， inducible nitric oxide synthase （iNOS）， cyclooxygenase-2 （COX-2） and tumor necrosis factor-α （TNF-α） （P<0.01）. Compared with LPS-induced group， 20-80 mg·L-1 XJD decreased the release of NO and IL-6 in a dose-dependent manner （P<0.01）， and similarly 10-80 mg·L-1 XJD suppressed the mRNA expression of IL-1β， iNOS， COX-2 and TNF-α （P<0.01）. Compared with the control group， IL-4 obviously increased the expression of M2 macrophage markers （P<0.01）， including increased CD206+ cell population and upregulated mRNA expression of arginine-1 （Arg-1）， interleukin-10 （IL-10）， interleukin-13 （IL-13） and transforming growth factor-β1 （TGF-β1）. Compared with IL-4-induced group， 10-80 mg·L-1 XJD dose-dependently decreased CD206+ cell population （P<0.01） and inhibited the mRNA expression of Arg-1， IL-10， IL-13 and TGF-β1 （P<0.01）. Western blot showed that XJD significantly downregulated the activation of PI3K/Akt pathway as compared to LPS- and IL-4-induced groups （P<0.05， P<0.01）. ConclusionXJD significantly inhibited the macrophage polarization in the LPS- and IL-4-induced RAW264.7 cells by targeting PI3K/Akt pathway.