ABSTRACT
ObjectiveTo observe the effects of Dendrobium polysaccharides on the secretion of inflammatory cytokines and Toll-like receptor 4 （TLR4）/nuclear factor （NF）-κB pathway in 16HBE cells exposed to cigarette smoke extract （CSE）. MethodThe 16HBE cells were classified into the control， CSE， and CSE+ Dendrobium polysaccharides （100， 200， 400 mg·L-1） groups. The cell-counting kit-8 （CCK-8） assay was employed to measure the cell viability， and a microscope was used to observe the cell morphology. The enzyme-linked immunosorbent assay was employed to measure the levels of interleukin （IL）-8， IL-1β， IL-4， IL-13， and transforming growth factor （TGF）-β in cell culture supernatants. Real-time PCR was carried out to determine the mRNA levels of Toll-like receptor 4 （TLR4）， nuclear factor-κB （NF-κB）， and IL-4. Western blot was employed to determine the protein levels of interleukin-4 receptor （IL-4R）， TLR4， myeloid differentiation primary response protein 88 （MyD88）， NF-κB， phosphorylated nuclear factor-κB （p-NF-κB）， and nucleoproteins nuclear factor-κB （NEs-NF-κB）. The immunofluorescence assay was employed to measure the nuclear translocation of NF-κB. ResultCompared with the control group， the CSE group showed elevated levels of IL-8， IL-1β， IL-4， IL-13， and TGF-β in the cell culture supernatants （P<0.05， P<0.01）， up-regulated expression levels of TLR4， MyD88， NF-κB， p-NF-κB， NEs-NF-κB， and IL-4 （P<0.01）， and significant nuclear translocation of NF-κB. Compared with the CSE group， Dendrobium polysaccharides increased the cell survival rate， recovered the cell activity， lowered the levels of IL-8， IL-1β， IL-4， IL-13， and TGF-β， down-regulated the expression of TLR4， MyD88， NF-κB， p-NF-κB， NEs-NF-κB， and IL-4 （P<0.05， P<0.01）， and reduced the nuclear translocation of NF-κB. ConclusionDendrobium polysaccharides showed significant protective effects on the 16HBE cells exposed to CSE by inhibiting the TLR4/NF-κB signaling pathway.