丙酮酸乙酯对脓毒症急性肺损伤大鼠的作用及其机制研究

Effect of ethyl pyruvate on acute lung injury induced by sepsis

目的探讨丙酮酸乙酯(EP)对脓毒症急性肺损伤(ALI)大鼠的作用及其可能的作用机制。方法选取健康成年雄性SD大鼠40只,采用随机数字表法分为对照组、假手术组、ALI组和EP组,每组10只。ALI组和EP组采用盲肠结扎穿孔法复制大鼠脓毒症模型,假手术组仅翻动盲肠,不做结扎穿孔。EP组术后腹腔注射EP溶液(40 mg/kg,间隔6 h),对照组、假手术组和ALI组腹腔注射等量乳酸林格液(间隔6 h)。模型复制24 h后心脏采血处死大鼠。酶联免疫吸附试验检测肺组织匀浆中高迁移率族蛋白B1(HMGB1)、Toll样受体4(TLR4)及核因子κB(NF-κB)的表达;计算肺组织湿干重比;HE染色后光镜下观察肺组织病理结构变化。结果ALI组、EP组HMGB1、TLR4及NF-κB水平高于假手术组(P<0.05),且EP组低于脓毒症ALI组(P<0.05);对照组与假手术组HMGB1、TLR4及NF-κB水平比较,差异无统计学意义(P>0.05)。ALI组、EP组肺组织湿干重比高于假手术组(P<0.05),且EP组低于ALI组(P<0.05);对照组与假手术组肺组织湿干重比比较,差异无统计学意义(P>0.05)。对照组和假手术组肺组织结构完整,肺泡间隔无水肿、炎症;ALI组肺泡结构破坏严重,肺泡间隔增宽,肺间质明显渗出、出血和大量炎症细胞浸润;EP组肺泡结构较完整,与ALI组相比,肺间质渗出、出血及炎症细胞浸润症状明显减轻。结论EP可能通过抑制HMGB1/TLR4/NF-κB信号通路,减轻肺组织炎症反应,改善肺损伤程度从而对脓毒症ALI发挥保护作用。

Objective To explore the protective effect of ethyl pyruvate on acute lung injury induced by sepsis and its possible mechanism.Methods Forty healthy adult male Sprague–Dawley rats were randomized into 4 groups(n=10 each)using a random number table:normal control group(Normal group),sham operation group(Sham group),sepsis lung injury group(ALI group)and ethyl pyruvate intervention group(EP group).A rat model of sepsis was prepared by cecal ligation and puncture.In Sham group,the cecum was only flipped but not ligationed and punctured.In EP group,ethyl pyruvate solution(40 mg/kg,every 6 h)was injected intraperitoneally after operation.In Normal,Sham and ALI groups were injected intraperitoneally with the same volume of lactated Ringer’s solution(every 6 h).The rats were killed 24 hours after model establishment.The expression levels of HMGB1,TLR4 and NF-κB in lung homogenate were detected by ELISA.The wet and dry lung weight ratio(W/D)of lung tissue was calculated,and after hematoxylin-eosin staining,pulmonary pathological changes were observed by light microscope.Results The expressions of HMGB1,TLR4,NF-κB in the lung tissue homogenate and lung tissue W/D were significantly different among groups(P<0.05);compared with sham group,the expressions of HMGB1,TLR4,NF-κB and lung tissue W/D in ALI group were increased(P<0.05);compared with sham group,the expressions of HMGB1,TLR4,NF-κB and lung tissue W/D in EP group were increased(P<0.05);compared with ALI group,the expressions of HMGB1,TLR4,NF-κB and lung tissue W/D in EP group were decreased(P<0.05).There were no significant difference in each detection index between normal and sham groups(P>0.05).Under light microscope,the structure of lung tissue was intact in normal and sham groups,there was no edema and inflammation in alveolar septum;in ALI group,the alveolar structure was severely damaged,the alveolar septum was widened,and exudation,hemorrhage and massive inflammatory cell infiltration could be observed in the pulmonary interstitial;compared with ALI group,the alveolar structure of EP group was relatively intact,the alveolar exudation,hemorrhage and inflammatory cell infiltration were significantly alleviated.Conclusions Ethyl pyruvate may reduce the inflammatory response and improve the degree of lung injury by inhibiting the activation of HMGB1/TLR4/NF-κB signaling pathway,thereby providing significant protection against acute lung injury induced by sepsis.