Abstract: Objective:To explore the expression level of Leucine-rich alpha-2-glycoprotein 1 (LRG1) in rats with acute lung injury caused by sepsis.Methods:Twenty-four SPF male SD rats were randomly divided into control group, 6 h group with sepsis lung injury(6 h group), 12 h group with sepsis lung injury(12 h group)and 24 h group with sepsis lung injury(24 h group), with 6 rats in each group.The rat model of acute lung injury with sepsis was established by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg).The rats in the control group were intraperitoneally injected with the same dose of normal saline (10 mL/kg).The expression of LRG1 mRNA in lung tissue was detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR).The concentration of LRG1 in rat serum was determined by enzyme-linked immunosorbent assay (ELISA).The pathological characteristics of lung tissue were observed by hematoxylin-eosin (HE) staining.The localized expression of LRG1 in lung tissue was observed by immunohistochemical staining.The expression of LRG1 protein in lung tissue was detected by western blotting.Results:Compared with the control group, the lung tissue of the rats with acute lung injury caused by sepsis showed inflammatory cell infiltration, thickening of the alveolar wall, and widening of the alveolar septum, which was consistent with the characteristics of lung injury caused by sepsis.LRG1 was expressed in both alveolar epithelial cells and inflammation-infiltrated immune cells.Compared with the control group, the serum LRG1 levels of the 6 h group, 12 h group and the 24 h group increased; the relative expression level of LRG1 mRNA in lung tissue of the 6 h group was higher than that of the control group(P< 0.05); LRG1 protein expression in the lung tissue of the 24 h group was higher than that of the control group(P< 0.05).Conclusion:LRG1 expression increases in the rat model of acute lung injury caused by sepsis.