芪冬活血饮对急性肺损伤小鼠肺泡巨噬细胞iRhom2/TACE信号通路的影响

Effect of Qidong Huoxue Decoction on iRhom2/TACE Signaling Pathway in Alveolar Macrophages of Acute Lung Injury Mice

[目的]探索芪冬活血饮对肠缺血/再灌注诱导的急性肺损伤小鼠肺泡巨噬细胞未活化的菱形蛋白2(inactive rhomboid protein 2,iRhom2)/肿瘤坏死因子-α转化酶(tumor necrosis factor-αconvertase,TACE)信号通路的影响。[方法]通过肠缺血/再灌注方法构建急性肺损伤小鼠模型。24只无特定病原体(specific pathogen free,SPF)级雌性C57BL/6小鼠被随机分为6组,每组4只,即正常组,假手术组,模型组,芪冬活血饮低(2m L·kg^(-1))、中(4mL·kg^(-1))、高(8mL·kg^(-1))剂量组。芪冬活血饮低、中、高剂量组小鼠在造模前24、12h以及造模后2、14h分别用2、4、8m L·kg^(-1)芪冬活血饮灌胃,2次/d,共4d;模型组予等量的0.9%氯化钠溶液灌胃;正常组和假手术组不给药。末次给药24h后,分离并培养肺泡巨噬细胞。以酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)检测巨噬细胞分泌肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白介素-6(interleukin-6,IL-6)的水平。以末端标记法(terminal-deoxynucleoitidyl transferase mediated nick end labeling,TUNEL)染色分析肺上皮细胞凋亡情况。实时荧光定量聚合酶链反应(Real-timequantitative polymerase chain reaction,RT-qPCR)和Western blot检测肺泡巨噬细胞中iRhom2和TACE的m RNA和蛋白表达水平。[结果]与假手术组比较,模型组小鼠肺泡巨噬细胞TNF-α和IL-6分泌水平显著增加(P<0.0001);经芪冬活血饮治疗后,TNF-α和IL-6水平以浓度依赖的方式显著降低(P<0.01,P<0.001,P<0.0001)。TUNEL结果显示,芪冬活血饮显著抑制急性肺损伤模型小鼠的肺上皮细胞凋亡(P<0.05,P<0.01,P<0.001)。与假手术组比较,模型组小鼠巨噬细胞中iRhom2和TACE m RNA和蛋白表达被显著激活(P<0.001,P<0.0001,P<0.01);经芪冬活血饮治疗后,巨噬细胞中iRhom2和TACE表达以浓度依赖的方式显著降低(P<0.05,P<0.001,P<0.0001)。[结论]芪冬活血饮能够有效改善肠缺血/再灌注诱导的急性肺损伤,其机制可能与抑制小鼠肺泡巨噬细胞中iRhom2/TACE信号通路有关。

[Objective]To explore the effect of Qidong Huoxue decoction on inactive rhomboid protein 2/tumor necrosis factor-α convertase(iRhom2/TACE)signaling pathway of alveolar macrophages in mice with acute lung injury induced by intestinal ischemia/reperfusion. [Methods] In this study,a mouse model of acute lung injury induced by intestinal ischemia/reperfusion was constructed by clamping the superior mesenteric artery for 1 hour and reperfusion for 3 hours. Twenty-four female C57 BL/6 mice were randomly divided into six groups,including normal group,sham operation group,model group,Qidong Huoxue decoction low-dose group(2 mL·kg^(-1)),Qidong Huoxue decoction medium-dose group(4 mL·kg^(-1)) and Qidong Huoxue decoction high-dose group(8 mL·kg^(-1)),with 4 mice in each group. Mice in Qidong Huoxue decoction low,medium,and high-dose groups were given 2,4 and8 mL·kg^(-1) Qidong Huoxue decoction 24,12 h before modeling and 2,14 h after modeling,respectively.After that,the drug was administered twice a day for a total of 4 days. Model group was given the same amount of 0.9% sodium chloride aqueous solution. No treatment was given in normal group and sham operation group. Twenty-four hours after the last administration,the alveolar macrophages were isolated and cultured. The level of tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) secreted by macrophages was detected by enzyme-linked immunosorbent assay(ELISA). Terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL) test was used to analyze the apoptosis of lung epithelial cells. The m RNA and protein levels of iRhom2 and TACE in alveolar macrophages were detected by Real-time-quantitative polymerase chain reaction(RT-qPCR) and Western blot,respectively.[Results] Compared with sham operation group,the levels of TNF-α and IL-6 secreted by the alveolar macrophages in model group were significantly increased(P <0.0001). Qidong Huoxue decoction distinctly inhibited the levels of TNF-α and IL-6 in a concentration-dependent manner(P <0.01,P <0.001,P<0.0001). TUNEL results showed that Qidong Huoxue decoction significantly inhibited the apoptosis of lung epithelial cells in mice with acute lung injury in a concentration-dependent manner(P<0.05,P<0.01,P<0.001). Compared with sham operation group,both m RNA and protein expression of iRhom2 and TACE was significantly activated in the macrophages of model group(P<0.001,P<0.0001,P<0.01). However,after treatment with Qidong Huoxue decoction,the expression of iRhom2 and TACE in macrophages was significantly suppressed in a concentration-dependent manner( P<0.05,P<0.001,P<0.0001).[Conclusion] Qidong Huoxue decoction can improve acute lung injury induced by intestinal ischemia/reperfusion,the mechanism may be related to the Rhibition of iRhom2/TACE signaling pathway in mouse alveolar macrophages.