[Abstract]Objective Acute lung injury is a common critical clinical illnesses. Recent studies showed that the incidence of ALI of rats is recognized to be closely related to antioxidization.The purpose of this study was to explore therapeutic effect of breviscapine by pulmonary delivery on rat with acute lung injury induced by lipopolysaccharide(LPS) from antioxidantion pathway.Methods Healthy male adult Sprague-Dawley rats were randomly divided into four groups:①Normal compared group:Animals were intratracheally instilled 0.2mL with sterile saline.②Breviscapine group:Animals were intratracheally instilled 50mg/Kg breviscapine.③ALI group:Animals were given 1μL/g LPS(0.05%) intratracheally.④Pulmonary breviscapine deliver group:Animals were intratracheally received 50mg/Kg; 100mg/Kg and 200mg/Kg breviscapine,following given 1mL/g LPS intratracheally after 1h.All rats were killed at 8h to detect indexes,respectively.Lung tissues were observed on light microscope by HE staining.Lung W/D ratio was detected.Tolal protein concents BALF was measured by the Coomassie brilliant blue method.O_2~(·-) and MDA contents,and SOD,GSH-PX and MPO activity in lung tissues were detected by biological chemistry methods.Differences between groups were statistically analyzed by one-way ANOVA,and the differences between the means of groups were separated by least significant difference(LSD) test.All data were presented as mean±standard error.Values of P＜0.05 were regarded as significant.A computer program(SPSS 11.5) was used for statistical analysis.Results①Histopathological evaluation.Typical pathological inflammation lesions in the lung were observed in ALI group,including alveolar congestion,hemorrhage,edema,infiltration of neutrophils in the airspace or vessel wall,thickness of the alveolar wall.Pathological changes in Pulmonary breviscapine deliver group were decreased obviously compared to ALI group.②W/D ratio in lung tissue.Compared to Normal compared group and Breviscapine group, W/D ratio in ALI group is higher(P＜0.05).W/D ratio in Pulmonary breviscapine deliver group is lower than ALI group(P＜0.05).③MPO activity and protein concentration in BALF in lung tissue.Compared with Normal compared group and Breviscapine group,ALI group is higher(P＜0.05).Pulmonary breviscapine deliver group is lower than ALI group(P＜0.05).④MDA and O_2~(·-) contents in lung tissues. Compared with Normal compared group and Breviscapine group,ALI group is higher (P＜0.05).Pulmonary breviscapine deliver group is lower than ALI group(P＜0.05).⑤SOD and GSH-PX activity in lung tissues.Compared with Normal compared group and Breviscapine group,ALI group is lower(P＜0.05).Pulmonary breviscapine deliver group is higher than ALI group(P＜0.05).Conclusions 1.Mechanism of ALI induced by LPS may be concerned with oxidative damage.2.Pulmonary breviscapine deliver can decrease the damage of lung tissue,the mechanism may be due to rise antioxidantion in lung.3.Pulmonary delivery of Breviscapine has no effect on the structure of normal lung tissue in short time.