Effects ofXuanbai Chengqi Decoction on Lung of Expressions of MD-2 and MyD88 mRNA and Protein in Rats with Acute Lung Injury Caused by Lipopolysaccharide

Objective:To investigate the effects of Xuanbai Chengqi Decoction on lung of expressions of MD-2 mRNA and MyD88 protein and its mRNA in the rats with acute lung injury caused by lipopolysaccharide(LPS).Methods:Thirty-two male Wistar rats were randomly divided into four groups:normal comparison control,model comparison group,dexamethasone group and Xuanbai Chengqi Decoction group.Each group had eight rats.The ALI rat model was established by LPS through intravenous tail injection(6 mg/kg).The rats in Xuanbai Chengqi Decoction group were pretreated by Xuanbai Chengqi Decoction(7.56 g/kg)for 3 days before LPS-induced ALI.The rats in dexamethasone group were pretreated by dexamethasone(5 mg/kg).The MD-2 mRNA and MyD88 protein and its mRNA were measured by immunohistochemistry(ABC)and real-time fluorescent Polymerase chain reaction(PCR).While the histopathology of the lung injury was observed by light microscope.Results:Compared with normal group,the expressions of MD-2 mRNA and MyD88 protein and its mRNA were obviously increased in model group(P0.01).Compared with model group,the expressions of MD-2 mRNA and MyD88 protein and its mRNA were obviously decreased in Xuanbai Chengqi Decoction and dexamethasone groups(P0.01),and there was no obvious difference between the Xuanbai Chengqi Decoction and dexamethasone group(P0.05).Light microscope observation indicated that there were large areas of pulmonary hemorrhage and necrosis in model comparison group,while in the Xuanbai Chengqi Decoction and dexamethasone group,the pathological manifestations were much more ameliorated than those of the model group.The lung bronchiole may inflammation sometimes,and the edema was light.Conclusion:Xuanbai Chengqi Decoction lessens the injury of lung tissue and has protective effects on rats with ALI induced by LPS;the mechanism is possibly related to the inhibition of the expressions of MD-2 mRNA and MyD88 protein and its mRNA in injured lung tissues.