ObjectiveTo study the protective effect and mechanism of ophiopogonin D (OP-D) on lipopolysaccharide induced acute lung injury (ALI) in mice.MethodsFifty SPF C57BL/6 mice were randomly divided into five groups, ie. a control group, a sham operation group, a model group, an OP-D group (10 mg·kg–1·d–1), and a dexamethasone group (2 mg·kg–1·d–1), with 10 mice in each group. One day before the establishment of the model, the OP-D group and the dexamethasone group received the corresponding drugs by gavage. The model group, the OP-D group and the dexamethasone group received lipopolysaccharide (2 mg/kg, 30 μL) through the trachea to establish the ALI model. The sham operation group received the same volume of normal saline. The blank control group was not treated. Six hours after the operation, the mice were weighed and then killed for peripheral blood and lung tissue. The weight of lung tissue was measured to evaluate the degree of pulmonary edema; the pathological changes of lung tissue were observed by hematoxylin-eosin staining; the mRNA expressions of interleukin (IL)-6, IL-10, and IL-17 in lung tissue were detected by qPCR; the percentage of Th17 and Treg cells in peripheral blood was detected by flow cytometry.ResultsCompared with the model group, the degree of pulmonary edema in the OP-D group decreased significantly (P<0.05), the lung tissue injury decreased, the mRNA expressions of IL-6 and IL-17 in the lung tissue and the proportion of Th17 cells in the peripheral blood decreased significantly (P<0.05), the proportion of Treg cells in the peripheral blood and the mRNA expression of IL-10 in the lung tissue increased significantly (P<0.05).ConclusionOP-D may have therapeutic effect on LPS induced ALI in mice by regulating the balance of Th17/Treg cells.