Objective:To explore the role of neutrophil extracellular traps(NETs)in promoting the secretion of inflammatory mediators by alveolar type epithelial cells(AECII).Methods:In 30 7 d born SD rats,blood was drawn from neutrophils(NE)and di-vided into control(control group),LPS and LPS+DNase groups according to different treatment methods.NETs formation was detec-ted by immunofluorescence in vitro.NETs and AECII were co-cultured,and divided into control group(control group),NETs group and NETs+DNase group according to cell suspension incubation method.AECII apoptosis was detected by flow method,the content of free deoxyribonucleic acid(cf-DNA)in coculture supernatants in each group was detected by fluorescence microarray,and the coculture su-pernatants of interleukin 6(IL-6),interleukin 8(IL-8)and tumor necrosis factor(TNF-α)in each group were determined using ELISA kit.And,the correlation between cf-DNA and IL-6,IL-8,and TNF-α was evaluated using Pearson correlation analysis.Results:According to immunofluorescence,mouse citrullinated histone H3(CitH3)and myeloperoxidase(MPO)were found in neutrophil in LPS and LPS+DNase group,CitH3 and MPO levels in LPS and LPS+DNase groups were higher than in the control group(P<0.05),and CitH3 and MPO in LPS+DNase group were lower than those in LPS group(P<0.05).After AECII apoptosis with NE and NETs,there was no significant difference between early and late apoptosis in the three groups(P＞0.05).The levels of cf-DNA,IL-6,IL-8,and TNF-α in NETs group and NETs+DNase group were higher than those of the control group(P<0.05),NETs+DNase group was lower than NETs group(P<0.05).The content of cf-DNA in cell culture supernatant was positively correlated with the levels of IL-6,IL-8,and TNF-α(r=0.432,0.387,0.326,P<0.05).Conclusion:AECII with NETs in the supernatants with NE,NETs could promote the secretion of inflammatory mediators such as IL-6,IL-8,and TNF-α.Moreover,the more NETs are generated,the more inflammatory mediators such as IL-6,IL-8,and TNF-α are secreted.