Objective To investigate the effects of modified Yupingfeng Powder medicated serum on the inflammatory response of rat lung epithelial type Ⅱ cells RLE-6TN;To explore the mechanism based on nuclear factor(NF)-κB signaling pathway.Methods The inflammatory reaction of RLE-6TN cells was induced by lipopolysaccharide,and the cells were divided into control group,model group,dexamethasone medicated serum group,and 5%,10%and 20%TCM serum group,and the cell model was intervened with different serum.After 24 hours,the content of lactate dehydrogenase(LDH)in cell supernatant was detected by kit,and the content of reactive oxygen species(ROS)in cells were detected by fluorescence staining,Hoechst/PI double staining was used to observe cell apoptosis,and ELISA was used to detect tumor necrosis factor-α(TNF-α),interleukin(IL)-6,and IL-1β contents in cell supernatant,RT-qPCR was used to detect Toll like receptor 4(TLR4),myeloid differentiation factor 88(MyD88),and NF-κB inhibitory protein α(IκBα)mRNA expression,Western blot was used to detect protein expressions of TLR4,MyD88,NF-κBp65 and IκBα.Results Compared with the control group,the contents of LDH,TNF-α,IL-6,IL-1β in RLE-6TN cell supernatant and ROS content in cells of model group significantly increased(P<0.01),the cell apoptosis rate significantly increased(P<0.01),the expressions of TLR4 and MyD88 mRNA and protein significantly increased(P<0.01),the expression of IκBα mRNA significantly decreased(P<0.01),and the ratio of p-NF-κBp65/NF-κBp65 and p-IκBα/IκBα significantly increased(P<0.01).Compared with the model group,the content of LDH,TNF-α,IL-6,IL-1 in RLE-6TN cell supernatant and ROS content in cells significant decreased in the 20%TCM serum group and dexamethasone medicated serum group(P<0.01),the cell apoptosis rate significantly decreased(P<0.01),the expressions of TLR4 and MyD88 mRNA and protein significantly decreased(P<0.05,P<0.01),the expression of IκBα mRNA significantly increased(P<0.01),and the ratio of p-NF-κBp65/NF-κBp65 and p-IκBα/IκBα significantly decreased(P<0.05,P<0.01).Conclusion Modified Yupingfeng Powder medicated serum can reduce RLE-6TN cells inflammatory reaction,and its mechanism may be related to the regulation of NF-κB signaling pathway.