Actions of NO and iNOS on endotoxin induced rat acute lung injury and affection of rhubarb on them

Objective To approach mainly the actions of nitric oxide(NO)and inducible nitric oxide synthase (iNOS) on endotoxin (lipopolysaccharidePaO 26 7kPa,LPS)induced rat acute lung injury (ALI) and the affeciton of rhubarb on them.Methods LPS was injected into the subingual vein of male Wistar rats to prepare ALI animal models.The rats were divided into the 4 groups:LPS group,control group,rhubarb group and dexamethasone group.Macroscopic and histopathological examinations were performed and biological indexes were measured for the lung specimens.The indexes included lung wet weight/dry weight,the rats of neutrophils and protein content in the pulmonary alveolar lavage fluid,pulmonary vascular permeability and pulmonary alveolar permeability index.In the mean time,the activities of serum NO and lung tissue homogenate iNOS were measured.Results In the comparison of the lung histopathological examination between the LPS group and control group,the injury and cellular infiltration in the pulmonary stroma and alveoli were more prominent in the LPS group than in the control group.Lung wet weight/dry weight,rat of neutrophils,protein content,pulmonary alveolar permeability index,pulmonary vascular permeability were significantly increased ( P 0 01);NO and iNOS were also markedly elevated ( P 0 01).In the groups with dexamethasone and rhubarb intering treatment,the histopathological changes were singnificantly milder,and the above biological indexes of lung injury and the contents of NO and iNOS were correspondingly decreased ( P 0 05).Conclusions From the LPS induced ALI rat models,it is demonstrated that NO and iNOS play important roles in the onset of ALI:dexamethasone and rhubarb interfering treatment can ameliorate,the lung injury and decrease the concentrations of NO and iNOS,showing that these 2 agents have protective effect on LPS induced ALI and their therapeutic mecharnism is possibly through inhibiting the activities of NO and iNOS. [