异丹叶大黄素对脂多糖诱导的小鼠急性肺损伤的影响

目的 探究异丹叶大黄素(ISO)对脂多糖(LPS)诱导的小鼠急性肺损伤(ALI)的保护作用及潜在机制。方法 体外培养RAW264.7细胞,采用不同浓度ISO处理细胞,CCK-8法检测细胞活力。使用200 ng/ml LPS诱导RAW264.7细胞,以ISO、自噬抑制剂3-甲基腺嘌呤(3-MA)进行干预,Western blot检测各组细胞中炎症介质白细胞介素(IL)-1β、IL-6、肿瘤坏死因子-α(TNF-α)、P65、磷酸化P65(p-P65)、IκB、磷酸化IκB(p-IκB)、诱生型一氧化氮合酶(iNOS)、环氧合酶2(COX-2)、高迁移率组蛋白B1(HMGB1)以及自噬相关蛋白LC3Ⅱ/Ⅰ、Beclin1、P62的表达,DCFH-DA探针检测各组细胞内活性氧(ROS)的变化。采用腹腔注射LPS(15 mg/kg)方法构建小鼠ALI模型,HE染色观察各组肺组织形态的病理变化,Western blot检测各组肺组织中炎症介质和自噬相关蛋白的表达,流式细胞术检测支气管肺泡灌洗液(BALF)中ROS的含量。结果 ISO可以抑制LPS诱导的RAW264.7细胞炎症因子IL-1β、IL-6、TNF-α、iNOS、COX-2、HMGB1的表达,抑制ROS的产生,促进LC3Ⅱ/Ⅰ、Beclin1的表达,降低P62的表达,激活自噬通路(P均<0.05);当使用自噬抑制剂3-MA干预后可显著增加p-P65/P65、p-IκB、iNOS、COX-2、HMGB1的表达且降低IκB的表达(P均<0.001),并促进ROS的产生。ISO能够改善LPS诱导的ALI小鼠的肺组织病理变化,显著抑制肺组织中p-P65/P65、p-IκB、iNOS、COX-2、HMGB1的表达且促进IκB的表达(P均<0.001),减少BALF中ROS的含量,3-MA则会逆转ISO的保护作用。结论 ISO对LPS诱导的ALI小鼠具有保护作用,其机制可能与ISO激活巨噬细胞自噬有关。

Effects of Isorhapontigenin on Lipopolysaccharide-Induced Acute Lung Injury in Mice

Objective To investigate the effect and mechanism of isorhapontigenin (ISO) in the protection of mice from the lipopolysaccharide (LPS)-induced acute lung injury (ALI). Methods RAW264.7 cells were cultured in vitro with different concentrations of ISO and the viability of the cells was measured by CCK-8 assay.Further,RAW264.7 cells were induced with 200 ng/ml LPS and then treated with ISO and the autophagy inhibitor 3-methyladenine (3-MA).Western blotting was employed to determine the expression of inflammatory cytokines interleukin (IL)-1β,IL-6,tumor necrosis factor-α (TNF-α),P65,phospho-P56 (p-P65),IκB,phospho-IκB (p-IκB),inducible nitric oxide synthase (iNOS),cyclooxygenase-2 (COX-2),and high mobility group box-1 (HMGB1)] and autophagy markers (LC3Ⅱ/Ⅰ,Beclin1,and P62).The reactive oxygen species (ROS) production of the cells was measured with the DCFH-DA probe.The mouse model of ALI was established by intraperitoneal injection of LPS (15 mg/kg).The pathological changes of the lung tissue were observed via HE staining.The expression of inflammatory cytokines and autophagy markers in the lung tissue was determined by Western blotting and the content of ROS in bronchoalveolar lavage fluid (BALF) by flow cytometry. Results ISO down-regulated the expression of IL-1β,IL-6,TNF-α,iNOS,COX-2,and HMGB1 and inhibited the ROS production in the LPS-induced RAW264.7 cells (all P<0.05).Furthermore,it promoted the expression of LC3Ⅱ/Ⅰ and Beclin1 and inhibited the expression of P62,thereby activating autophagy (all P<0.05).However,the addition of 3-MA up-regulated the expression of p-P65/P65,p-IκB,iNOS,COX-2,and HMGB1,down-regulated that of IκB (all P<0.001),and promote the production of ROS.ISO mitigated the pathological changes in the lung tissue of ALI mice.It down-regulated the expression of p-P65/P65,p-IκB,iNOS,COX-2,and HMGB1 and up-regulated that of IκB in the lung tissue (all P<0.001) and decreased the ROS production in BALF.However,such protective effect was reversed by 3-MA. Conclusion ISO may induce autophagy of macrophages to protect mice from LPS-induced ALI.