Objective:To study the effects of sivelestat sodium atomization inhalation on secondary lung injury by aspiration in severe brain injury rats and to explore its mechanism from the perspective of inflammatory reaction.Methods:60 SD rats were randomly divided into six groups:normal group(A)

aspiration group(B)

aspiration of brain injury group(C)

saline control group(D)

dexamethasone atomization inhalation group(E)

and sivelestat sodium atomization inhalation group(F)

10 rats in each group.Neutrophil elastase(NE) and interleukin-8(IL-8) content in bronchoalveolar lavage fluid(BALF) were detected by using enzyme-linked immunosorbent assay(ELISA).Immune turbidimetry was used to determine the albumin concentration in the BALF.Pathological changes in lung tissue were observed by optical microscope.Results:The changes of Morphological characteristic of the lung tissue in F group were improved most significantly

the following was E group.The contents of NE in the BALF in group E and F were lower than that in group B

C and D(P <0.05)

and The contents of NE in group F were reduced most obviously in all groups.The contents of IL-8 in the BAlF between group E and F showed no significant difference(P>0.05)

which were lower than those in group C and D(P <0.05).Conclusion:Sivelestat sodium and dexamethasone atomization inhalation have a positive effect on the rats of brain injury with secondary inhalation lung injury

but sivelestat sodium is superior to dexamethasone

and its mechanism may be that sivelestat sodium may inhibit the production of NE and its activities and alleviate the direct injury of lung tissue induced by NE and inhibit the lung injury caused by the inflammatory reaction of the lung.