宣白承气汤对内毒素致急性肺损伤大鼠肺组织MD-2mRNA、MyD88蛋白及其mRNA表达的影响

目的：探讨宣白承气汤对脂多糖（LPS）诱导的急性肺损伤（ALI）大鼠肺组织髓样分化蛋白-2（myeloid differentiation protein-2,MD-2）mRNA、髓样分化因子88（myeloid differentiation factor 88,MyD88）蛋白及其mRNA表达的影响。方法：将32只雄性Wistar大鼠随机分为：正常对照组、模型对照组、地塞米松组、宣白承气汤组,每组8只。尾静脉注射LPS 6 mg/kg制备大鼠ALI模型。宣白承气汤组在造模前灌胃3 d,按7.56g生药/kg宣白承气汤水煎液灌胃,1次/d;地塞米松组在造模前1 h按5 mg/kg腹腔注射地塞米松,造模6 h后麻醉取材。采用免疫组化ABC法和实时荧光定量聚合酶链反应（PCR）检测MD-2mRNA、MyD88蛋白及其mRNA的表达,并于光镜下观察大鼠肺组织病理变化。结果：与正常对照组相比,模型组MD-2mRNA、MyD88蛋白及其mRNA的表达均明显上调（P〈0.01）;与模型组相比,地塞米松组和宣白承气汤组MD-2mRNA、MyD88蛋白及其mRNA表达明显降低（P〈0.01）;地塞米松组和宣白承气汤组相比无显著差异（P〉0.05）。病理学观察,与正常组相比,模型对照组大鼠肺组织出现大片出血及坏死,宣白承气汤组和地塞米松组大鼠肺组织病理改变明显轻于模型对照组,肺细支气管偶见炎症改变,水肿较轻,炎性细胞渗出较少。结论：宣白承气汤能减轻内毒素致ALI大鼠肺组织损伤,对肺损伤有保护作用,其机制可能与其能降低内毒素致ALI大鼠MD-2mRNA、MyD88蛋白及其mRNA的表达有关。

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（P〉0.05）.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.