急性肺损伤大鼠模型制备及不同时段肺损伤比较

Preparation of rat model of acute lung injury and comparison of injury at different periods

目的通过气管滴注脂多糖(lipopolysaccharide,LPS)构建急性肺损伤大鼠模型,观察不同时段肺损伤变化规律。方法32只健康SD大鼠随机分为正常组、模型组,正常组8只大鼠,模型组24只大鼠。模型组依据LPS滴注时长不同分为三个亚组:3 h组、6 h组和12 h组,每组8只。以LPS(2 mg/kg)暴露式气管滴注法复制ALI大鼠模型。通过大鼠一般状况、肺大体观察、肺功能检测、计算肺湿干重比值、支气管肺泡灌洗液(BALF)中白细胞介素-1β(IL-1β)、白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)检测和肺组织中丙二醛(MDA)、超氧化物歧化酶(SOD)检测、苏木素-伊红染色(HE染色)组织形态学观察,评估不同时段急性肺损伤伤情变化情况。结果造模后模型组大鼠存活率为100%。大鼠一般状况显示,3 h组与正常组相比,精神处于淡漠状态、摄食减少、活动明显减少、鼻腔处粘液分泌物增多、大鼠的呼吸频率加快、可闻及哮鸣音。肺大体观察显示,3 h组左右肺门处可见肺组织肝样变,左右肺叶上散布出血点,出血部位颜色鲜红。肺功能显示3 h组大鼠第0.1秒用力呼气量(FEV0.1)、第0.3秒用力呼气量(FEV 0.3)以及各占用力肺活量(FVC)之比(FEV0.1/FVC;FEV0.3/FVC)均显著下降(P<0.05,P<0.01);肺湿干重比值明显升高(P<0.01);BALF中IL-1β、IL-8、TNF-α含量明显升高(P<0.01),MDA含量显著升高(P<0.01),SOD含量显著降低(P<0.01);HE染色可见明显肺泡间隔增厚、肺间质水肿、红细胞渗出。结论暴露式气管滴注LPS法,可以引起大鼠肺功能显著下降、剧烈的肺部炎症、氧化-抗氧化失衡及严重肺水肿和肺出血,导致急性肺损伤,在3 h时段更有利于ALI大鼠模型的构建。

Objective A rat model of acute lung injury(ALI)was established by intratracheal instillation of lipopolysaccharide(LPS)and changes in the lung injury were observed at various periods.Methods Thirty-two healthy Sprague-Dawley(SD)rats were randomly divided into normal(n=8)and model(n=24)group.In accordance with the duration of LPS infusion,the model group was divided into three subgroups:3,6 and 12 h groups,with eight rats in each group.The ALI rat model was established by tracheal instillation of LPS(2 mg/kg).Observations included the general performance of rats,gross observation of lungs,detection of lung functions,calculation of the lung wet/dry weight ratio,detection of interleukin(IL)-1β,IL-8,and tumor necrosis factor-αin bronchoalveolar lavage fluid,detection of malondialdehyde and superoxide dismutase in lung tissue,and histomorphological observation by hematoxylin-eosin staining in lung tissue.Changes of acute lung injury were also evaluated at different stages.Results After modeling,the survival rate of rats in the model group was 100%.Compared with the normal group,the general performances of rats in the 3 h group were similar with less food intake,less activity,more mucus secretions in the nasal cavity,faster respiratory frequency,and audible wheezing.Gross observation of the lungs showed liver-like degeneration of the lung tissue in the left and right hilum of the lung in the 3 h group,bleeding spots were scattered on the left and right lobes,and the bleeding site was bright red.The pulmonary functions of rats after LPS exposure for 3 h showed significant decreases in the forced expiratory volume(FEV)in 0.1 s,forced expiratory volume in 0.3 s,ratio of forced expiratory volume in 0.1 s to forced vital capacity,and ratio of forced expiratory volume in 0.3 s to forced vital capacity(P<0.05,P<0.01).The wet/dry weight ratio was increased significantly(P<0.01).The contents of IL-1β,IL-8,and tumor necrosis factor-αin bronchoalveolar lavage fluid were increased significantly(P<0.01).The content of malondialdehyde was increased significantly(P<0.01).The content of superoxide dismutase was decreased significantly(P<0.01).Hematoxylin-eosin staining showed obvious thickening of the alveolar septum,pulmonary interstitial edema,and erythrocyte exudation.Conclusions Tracheal instillation of LPS causes significant decreases in lung functions,severe pulmonary inflammation,an oxidation-antioxidation imbalance,and severe pulmonary edema in rats,which lead to acute lung injury.Furthermore,it is more beneficial to establish an ALI rat model at the 3 h time point.