ObjectiveTo explore the therapeutic effect of angiotensin-converting enzyme 2 (ACE2) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a rat model. MethodsTwenty-four Wistar rats were randomly divided into a control group, an ALI group, and an ACE2 group.The rat ALI model was established by intravenous injection of LPS.Then the rats in the ACE2 group received intraperitoneally injection of recombinant rat ACE2 by 0.1 mg/kg immediately after LPS injection.All rats were sacrificed 2 hours later.Rat arterial blood gas was analyzed and wet/dry (W/D) weight ratio of lung tissue was measured.Concentrations of TNF-α, IL-8 and IL-1βin lung tissue homogenates were measured by ELISA.Pulmonary pathological changes were evaluated by hematoxylin-eosin stain under light microscope. ResultsALI induced by LPS was successfully established in the rats.ACE2 pretreatment markedly impoved PaO2 level of the ALI rats(P < 0.05), and decreased the lung W/D ratio(P < 0.05).The concentration of TNF-α, IL-8 and IL-1βin lung tissue homogenates were also inhibited by ACE2.And the lung histopathological changes and score were attenuated in the ACE2 group. ConclusionACE2 treatment has therapeutic effects on ALI induced by LPS.