Abstract: Abstract: Objective To investigate the effects of sivelestat sodium on early inflammatory reaction of rats with smoke inhalation injury. Methods Forty healthy male SD rats were randomly divided into 3groups: normal group、injury group、treatment group。And treatment group was allocated into 3 groups: smoke inhalation group treated with10mg/kg sivelestat sodium group , 20mg/kg treatment group , 30mg/kg treatment group,8 rats each group , smoke inhalation injury model was established by using a smoke generator, the treatment groups were intraperitoneally injected sivelestat sodium 10mg/Kg、20mg/Kg、30mg/Kg separately， injury group were treated with the same volume physiological saline. All rats were executed after 24 hours ,take the blood and preserve their lung tissues. ELISA was used for detecting content of neutrophil elastase (NE)、myeloperoxidase（MPO）、tumor necrosis factor-α(TNF-α)、interleukin- 6(IL-6 )in serum in each group，partial lung tissue were used for detecting water content and observing their pathological changes by HE staining .Result Compared with control group ,the levels of serum NE 、MPO、 TNF-α、IL-6 and water content of the lung tissue were significantly higher in other groups（P＜0.05)；Compared with injury group，the levels of serum NE 、MPO、 TNF-α、IL-6 and water content of the lung tissue were significantly lower in each treatment group（P＜0.05) ;Compared with 20mg/kg treatment group、30mg/kg treatment group , the levels of serum NE 、MPO、 TNF-α、IL-6 and water content of the lung tissue were significantly lower in 10mg/kg treatment group（P＜0.05) ;And in this experiment ,the low dose of sivelestat sodium had the best treatment effect. Conclusion The result showed that sivelestat sodium can reduce the early inflammatory reaction of rats with smoke inhalation injury and attenuate the lung edema. In this experiment , the effect of the drug treatment group was inversely proportional to the dosage, and the concentration of 10mg/kg was better than that of other treatment groups.

Key words: Keywords: sivelestat sodium , inhalation injury , neutrophil elastase, ALI , Inflammatory factors