目的 探讨淫羊藿苷基于Rac1信号通路改善慢性阻塞性肺疾病（chronic obstructive pulmonary disease，COPD）模型小鼠肺泡巨噬细胞胞葬及吞噬功能障碍的作用机制。方法 40只C57BL/6小鼠随机分为空白组、模型组、Rac1抑制剂（2.5 mg/kg）组和淫羊藿苷低、高剂量（40、80 mg/kg）组，每组8只，除空白组外其余各组小鼠采用香烟烟雾熏吸8周的方法制备COPD模型，造模后ip Rac1抑制剂或ig淫羊藿苷，1次/d，每周给药6次，连续4周。检测小鼠体质量、肺功能指标；ELISA法检测肺组织中肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）、白细胞介素-4（interleukin-4，IL-4）、IL-6、乳脂球表皮生长因子8（milk fat globule EGF factor 8，MFG-E8）和生长停滞特异性蛋白6（growth arrest specific protein 6，GAS6）含量；流式细胞术检测肺泡巨噬细胞胞葬及吞噬能力、小鼠全血巨噬细胞M1/M2分型；苏木素-伊红染色（hematoxylin-eosin staining，HE）观察肺组织病理变化及肺泡平均截距（mean linear intercept，MLI）、单位面积平均肺泡数（mean alveolar numbers，MAN）；qRT-PCR和Western blotting分别检测肺组织Rac1、P21蛋白激活激酶（P21 activated kinase，PAK）mRNA和蛋白表达；激光共聚焦显微镜观察巨噬细胞吞噬及骨架结构变化。结果 与空白组比较，模型组小鼠体质量、肺功能指标、吞噬及胞葬功能降低（P＜0.05、0.01），MLI上升（P＜0.01），MAN降低（P＜0.01），肺组织中炎症因子IL-4、IL-6、TNF-α水平上升（P＜0.05、0.01），胞葬辅助因子MFG-E8、GAS6水平降低（P＜0.05），M1型巨噬细胞增多（P＜0.05），肺组织Rac1、PAK mRNA及蛋白表达上调（P＜0.05、0.01）；与模型组比较，Rac1抑制剂及淫羊藿苷干预后小鼠肺功能指标好转（P＜0.05、0.01），吞噬及胞葬功能均有改善（P＜0.05、0.01），炎症因子水平降低（P＜0.05、0.01），胞葬辅助因子水平增加（P＜0.05），M2型巨噬细胞增多（P＜0.05、0.01），肺组织Rac1、PAK mRNA及蛋白表达降低（P＜0.05、0.01）。结论 淫羊藿苷可以调控Rac1信号通路介导巨噬细胞骨架重排，改善COPD小鼠肺泡巨噬细胞吞噬及胞葬功能障碍。

Objective To investigate the mechanism of icariin in improving efferocytosis and phagocytosis dysfunction of alveolar macrophages in chronic obstructive pulmonary disease (COPD) model mice based on Rac1 signaling pathway. Methods A total of 40 C57BL/6 mice were randomly divided into blank group, model group, Rac1 inhibitor (2.5 mg/kg) group, icariin low- and high-dose (40, 80 mg/kg) groups, with eight mice in each group, except for the blank group, the rest groups of mice were prepared by cigarette smoke inhalation for eight weeks to prepare a mouse COPD model. After modeling, rats were ip Rac1 inhibitor or icariin, once a day, six times a week for four consecutive weeks. Body weight and lung function indices were detected; ELISA was used to detect levels of tumor necrosis factor-α (TNF-α), interleukin-4 (IL-4), IL-6, milk fat globule EGF factor 8 (MFG-E8) and growth arrest specific protein 6 (GAS6) in lung tissue; Flow cytometry was used to detect the efferocytosis and phagocytosis function of alveolar macrophages, and the M1/M2 phenotype of whole blood macrophages in mice; HE staining was used to observe the pathological changes of lung tissue, as well as mean linear intercept (MLI) and mean alveolar numbers (MAN); qRT-PCR and Western blotting were used to detect Rac1, P21 activated kinase (PAK) mRNA and protein expressions in lung tissue; Macrophage phagocytosis and structural changes of skeleton were observed by laser confocal microscopy. Results Compared with blank group, body weight, lung function indexes, phagocytosis and efferocytosis function of mice in model group were decreased (P < 0.05, 0.01), MLI was increased (P < 0.01), MAN was decreased (P < 0.01), inflammatory factors IL-4, IL-6 and TNF-α levels in lung tissue were increased (P < 0.05, 0.01), levels of efferocytosis cofactors MFG-E8 and GAS6 were decreased (P < 0.05), M1-type macrophages was increased (P < 0.05), Rac1, PAK mRNA and protein expressions in lung tissue were up-regulated (P < 0.05, 0.01). Compared with model group, lung function indexes were improved after the intervention with Rac1 inhibitor and icariin (P < 0.05, 0.01), phagocytosis and efferocytosis function were improved (P < 0.05, 0.01), levels of inflammatory factors were decreased (P < 0.05, 0.01), levels of efferocytosis cofactors were increased (P < 0.05), M2 type macrophages were increased (P < 0.05, 0.01), Rac1, PAK mRNA and protein expressions in lung tissue were decreased (P < 0.05, 0.01). Conclusion Icariin can modulate the Rac1 signaling pathway to mediate macrophage skeleton rearrangement and improve phagocytosis and efferocytosis dysfunction of alveolar macrophages in COPD mice.

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国家自然科学基金面上项目（81873285）；国家自然科学基金面上项目（82274438）；河南省特色骨干学科中医学学科建设项目（重点项目）（STG-ZYXKY-2020022）