Abstract: Abstract：　Objective　To investigate the immunoregulation mechanism of Astragalus Polysaccharide in lichen planus. Methods　 OLP inflammatory model was established by LPS stimulating HaCaT cells, and then the mRNA expressions of NF-κBP65,TLR-4,TNF-α,IL-1β,and IL-6 were detected by RT-PCR after APS treatment of HaCaT cells.The cell growth inhibition rate was detected by MTT assay. Results　 In vitro OLP inflammation model, the mRNA expressions of NF-κBP65, TLR-4, TNF-α, IL-1β, IL-6 were significantly decreased. The mRNA expressions of TLR-4 and IL-1βin in 6h were the lowest, the mRNA expressions of NF-κBP65, TNF-α, IL-6 mRNA in 24h were the lowest (P<0.001). What inhibited cell growth most obviously was 25μg/mlAPS treated cells for 24h .Conclusions　APS may inhibit the activation of TLR-4 to regulate the expression of NF-κB, and may also inhibit the expression of inflammatory factors through other signaling pathways, then ultimately alleviate the OLP inflammatory response and mucosal damage.

Key words: oral lichen planus, APS, immunoregulatory effect , TLRs/NF-κB