脂多糖经不同给药方式致急性肺损伤小鼠模型的比较研究

Comparison of Three Mouse Models of Acute Lung Injury Induced by Different Administration of Lipopolysaccharides

目的比较脂多糖(LPS)经三种不同给药方式复制急性肺损伤(ALI)小鼠模型的病理损伤特征及炎症反应程度,优化ALI小鼠造模方法。方法 BLAB/c小鼠麻醉后分别采用气管内雾化(ITA组)、气管内滴入(ITI组)和腹腔注射(IPI组)LPS(5 mg/kg)的方法复制ALI小鼠模型,同时用伊文斯蓝取代LPS显示气管内雾化和滴入时药物的肺内分布。LPS给药2 h后处死小鼠,分别取肺组织行干湿重比、HE染色及病理评分,Western blot检测肺组织IκB-α含量及IκB-α、NF-κB p65磷酸化水平,qRT-PCR检测肺组织TNF-α和IL-1βmRNA转录强度。结果 ITA组伊文斯蓝在小鼠各肺叶中分布较ITI组更均匀。LPS给药2 h后ITA组、ITI组和IPI组小鼠肺组织干湿重比和病理损伤评分均显著高于正常对照组(NC组,P<0.01),其中ITA组病理损伤评分最重(P<0.05)。Westernblot结果显示ITA组小鼠肺组织IκB-α降解程度、IκB-α和NF-κB p65磷酸化水平均显著高于ITI组(P<0.05),而ITI组又显著高于IPI组(P<0.05)。qRT-PCR结果显示ITA组小鼠肺组织TNF-α和IL-1βmRNA转录强度均显著高于ITI组(P<0.05),而ITI组又显著高于IPI组(P<0.05)。结论气管内雾化LPS造成的肺组织病理损伤和炎症反应更加广泛和严重,且具有手术创伤小、操作方便等特点,是复制急性肺损伤小鼠模型的优选方案。

Objective To compare three approaches of lipopolysaccharides （LPS） administration for inducing acute lung injury （ALI） in mice. Methods LPS （5 mg/kg） was intratracheally aerosol administered （ITA group）,intratracheally instilled （ITI group）, or intraperitoneally injected （IPI group） to induce ALI in BLAB/c mice. Evans Blue instead of LPS was intratracheally administered to observe the liquid distribution in the lungs. Two hours after LPS administration, the mice were sacrificed and the lungs were removed to determine wet-to-dry lung weight ratio （W/D）, and the histological changes were evaluated by HE staining. Phosphorylation level of IκB-α and NF-κB p65 in lung tissue were investigated by Western blot. Transcription intensity of TNF-α and IL-1β mRNA in lung tissue were detected by real-time quantitative PCR. Results Evans Blue distributed more uniformly in the ITA group than the ITI group. The lung W/D ratio and histological changes score in three LPS administration groups were all significantly higher than the normal control group （P 〈 0. 01 ） ,with the ITA group being the highest. The phosphorylation levels of IκB-α and NF-κB p65 were significantly higher in the ITA group than the ITI group （P 〈 0. 05 ）, and were significantly higher in the ITI group than the IPI group （P 〈 0. 05 ）. Transcription intensity of TNF-a and IL-1β mRNA was significantly higher in the ITA group than the ITI group （P 〈 0. 05）, and were significantly higher in the ITI group than the IPI group （P 〈 0. 05）. Conclusion Being non-invasive and convenient,intratracheal LPS aerosol inhalation is an optimal method to induce ALI in mice because it induces more extensive and uniformly distributed injuries in lung.