Objective To investigate effects of calycosin(CA)on cigarette smoke(CS)induced airway epithelial cell damage in mice and the sirtuin 3/superoxide dismutase 2(SIRT3/SOD2)signaling pathway in mice.Methods A total of 90 mice were randomly separated into the control group,the cigarette smoke(CS)group,the CA low-dose treatment group(CA-L group),the CA high-dose treatment group(CA-H group)and the CA high-dose treatment plus SIRT3 inhibitor 3-TYP group(CA-H+3-TYP group),with 18 mice in each group.Tidal volume(TV)and peak expiratory flow rate(PEF)of lung function were detected by whole body plethysmography system.Serum levels of inflammatory factors[interleukin(IL)-6,tumor necrosis factor(TNF)-α]and oxidative stress indicators[reactive oxygen species(ROS),SOD]were detected by enzyme-linked immunosorbent assay(ELISA).The injury of airway epithelial cells in lung tissue was observed by HE staining.The expression levels of barrier related proteins(OCLN and ZO-1)in airway epithelial cells were detected by immunohistochemistry.Immunoblotting was applied to detect the expression of SIRT3/SOD2 signaling pathway related proteins.Results Compared with the control group,levels of TV,PEF,MAN and SOD and the expression levels of OCLN,ZO-1,SIRT3 and SOD2 were decreased in the CS group,while the levels of MLI,IL-6,TNF-α and ROS were increased(P＜0.05).Compared with the control group,the lung tissue structure was significantly damaged,the alveolar enlargement was obvious,the surrounding alveolar was accompanied by inflammatory cell infiltration,and the airway epithelial cells were obviously shed in the CS group.Different doses of CA alleviated lung tissue destruction,improved alveolar structure,reduced inflammatory cell infiltration,reduced airway epithelial cell shedding,increased levels of TV,PEF,MAN,SOD and OCLN,ZO-1,SIRT3 and SOD2,and decreased levels of MLI,IL-6,TNF-α and ROS.The effect of high dose CA was more significant than that of low dose CA(P＜0.05).SIRT3/SOD2 signaling pathway inhibitor 3-TYP partially reversed the ameliorative effect of CA on CS induced airway epithelial cell injury in mice.Conclusion CA can ameliorate CS induced airway epithelial cell damage in mice,and its mechanism is related to the activation of the SIRT3/SOD2 signaling pathway.