盲肠结扎穿刺和脂多糖诱导大鼠急性呼吸窘迫综合征模型的建立和分析

Establishment and analysis of cecal ligation puncture and lipopolysaccharide induced acute respiratory distress syndrome in rats

目的研究盲肠结扎穿刺(CLP)和脂多糖(LPS)联合诱导建立大鼠急性呼吸窘迫综合征(ARDS)模型的可能性,探讨其意义和理论依据。方法将176只SD大鼠随机分为4组,每组44只。(1)CLP组;(2)尾静脉注射2 mg/kg LPS(LPS组);(3)CLP和尾静脉注射2 mg/kg LPS联合诱导(CLP+LPS组);(4)假手术后尾静脉注射2 ml/kg生理盐水(对照组)。每组分为4个亚组,分别在4、12、24、48 h检测大鼠呼吸频率,支气管肺泡灌洗液(BALF)中的白细胞总数、多形核白细胞百分比、总蛋白含量、肿瘤坏死因子α和白细胞介素6(IL-6)水平,测定肺湿干重比,对肺组织进行病理组织学观察和透射电镜观察。结果与对照组相比,呼吸频率、总蛋白含量、肿瘤坏死因子α、白细胞总数、多形核白细胞百分比、IL-6水平在4 h时LPS组和CLP+LPS组升高(P值均<0.05),CLP组在12 h升高(P值均<0.05),24 h时CLP组和CLP+LPS组升高(P值均<0.05),而LPS组趋于恢复。在所有时间点,CLP+LPS组的呼吸频率和IL-6水平升高(P值均<0.05)。病理形态学和透射电镜观察到24 h CLP+LPS组炎性反应、肺泡细胞损伤最为严重。结论CLP和LPS联合诱导建立的大鼠模型与单独的CLP和LPS模型相比,肺损伤出现早,持续时间长,在临床表现和肺损伤方面更接近ARDS的诊断标准,是一种较理想的ARDS模型。

Objective To investigate the possibility of cecal ligation puncture(CLP)combined with lipopolysaccharide(LPS)to establish acute respiratory distress syndrome(ARDS)model in rats,and to explore its significance and theoretical basis.Methods 176 SD rats were randomly divided into four groups,44 rats in each group:(1)CLP group;(2)injection of LPS(2 mg/kg)through tail vein(LPS group);(3)CLP combined with injection of LPS(2 mg/kg)through tail vein(CLP+LPS group);(4)injection of physiological saline(2 ml/kg)through tail vein after sham operation(control group).Each group was divided into four subgroups.The respiratory rate of rats,total number of white blood cells,percentage of polymorphonuclear leukocytes,total protein content,tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)in bronchoalveolar lavage fluid,and ratio of lung wet to dry weight were measured at 4th,12th,24th,and 48th hour.Observation of histopathological and transmission electron microscope on lung tissue was performed.Results Compared with the control group,the respiratory rate,total protein content,TNF-α,white blood cells,percentage of polymorphonuclear leukocytes,and IL-6 level increased at 4th hour in LPS group and CLP+LPS group(all P<0.05),and increased at 12th hour in CLP group(all P<0.05).The above parameters in CLP group and CLP+LPS group increased significantly at 24th hour(all P<0.05),while those tended to recover in LPS group.Respiratory frequency and IL-6 level were increased in CLP+LPS group at all time points(all P<0.05).The results of pathological morphology and transmission electron microscopy showed that the inflammatory response and alveolar cell damage were the most severe in CLP+LPS group at 24th hour.Conclusions Compared with the CLP or LPS models,lung injury is earlier and duration is longer in the rat models established by CLP combined with LPS.It is closer to the diagnostic criteria of ARDS on clinical manifestations and lung injury,and it is an ideal ARDS model.