Objective To investigate the changes of interleukin-17 ( IL-17) and the effects of propofol in rats with acute lung injury ( ALI) . Methods ALI model was established by hydrochloric acid ( HCl) inhalation in a dose of 2 mL/kg. 35 adultmale SD rats were randomly divided into seven groups, ie.a control group, a HCl group, and five propofol groups ( T24b , T12b , T0 , T1a , T3a groups, respectively) . The T0 ,T24b and T12b groups were pretreated with intraperitoneal propofol injection 0, 24 and 12 hours respectively before HCl inhalation. The T1a and T3a groups were managed by intraperitoneal propofol injection 1 and 3 hours respectively after HCl inhalation. Immunohistochemistry was used to determine the expression of IL-17 in lung tissue. ELISA was adopted to detect the levels of IL-17 and IL-8 in lung tissue homogenate as well as in bronchoalveolar lavage fluid ( BALF) , meanwhile arterial partial pressure of oxygen ( PaO2 ) and myeloperoxidase ( MPO) were measured. Results Those rats in the HCl group appeared respiratory distress, cyanosis, pulmonary edema, and inflammatory cells infiltration in lung tissues after HCl inhalation.The IL-17 levels in lung tissue homogenate as well as in BALF were higher in the HCl group than those in the control group( all P lt; 0. 01) . IL-17 was mainly expressed in alveolar epithelial cells and mononuclear cells in the ALI rats and its expression level was higher than that in the control group. IL-17 concentration in lung tissue homogenate was both correlated with IL-8 concentration in lung tissue homogenate ( r=0. 98, P =0.003) and with the activity of MPO in lung tissue( r=0. 981, P =0. 003) in the HCl group. Mainwhile, a same significant correlation was found between IL-8 level in lung tissue homogenate and the MPO activity in the HCl group( r =0. 961, P =0. 009) . Propofol attenuated lung injury induced by HCl inhalation, especially in T24b group. The concentrations of IL-17 in lung tissue homogenate and in BALF were lower in T24b group when compared with the HCl group( P = 0. 011, P =0. 003, respectively) . Conclusions The expression of IL-17 increases in ALI rats. Pretreatment with propofol by 24 hours has obvious inhibiting effects on inflammatory reaction. Inhibiting IL-17 expression may be one of the mechanisms through which propofol inhibits the inflammatory reaction of ALI.