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目的:评价鸢尾素对呼吸机相关性肺损伤(VILI)大鼠肺泡巨噬细胞极化的影响。方法:SPF级健康成年雄性SD大鼠30只，6~8周龄，体重200~250 g。采用随机数字表法将其分为3组(n n＝10)：对照组(C组)、VILI组(V组)和鸢尾素组(I组)。采用机械通气(潮气量20 ml/kg，通气频率80次/min，吸入氧浓度21%，吸呼比1∶2，呼气末正压为0)4 h方法制备大鼠VILI模型。C组保留自主呼吸4 h；I组于气管插管前30 min尾静脉注射鸢尾素1 μg/kg，其余组注射等容量生理盐水。机械通气4 h时处死大鼠，取肺组织，HE染色后行肺损伤评分，计算湿重/干重比值(W/D比值)；收集支气管肺泡灌洗液(BALF)，采用ELISA法测定BALF IL-6、TNF-α、IL-10浓度；采用Western blot法测定BALF诱导型一氧化氮合酶(iNOS)、精氨酸酶1(Arg-1)和肺泡巨噬细胞磷酸化NF-κB p65(p-NF-κB p65)、磷酸化NF-κB p50(p-NF-κB p50)表达水平；流式细胞术测定M1型、M2型肺泡巨噬细胞百分比及M1/M2比值。n 结果:与C组相比，V组肺组织W/D比值、肺损伤评分、BALF IL-6、TNF-α和IL-10浓度升高，iNOS和Arg-1、p-NF-κB p65及p-NF-κB p50表达上调，M1型和M2型肺泡巨噬细胞百分比增多，M1/M2比值升高(n P<0.05)。与V组相比，I组肺组织W/D比值、肺损伤评分、BALF IL-6和TNF-α浓度降低，iNOS和p-NF-κB p65表达下调，M1型肺泡巨噬细胞百分比减少，M1/M2比值降低(n P0.05)。n 结论:鸢尾素减轻VILI大鼠炎症反应的机制可能与抑制NF-κB信号通路激活，减轻肺泡巨噬细胞向M1型极化有关。“,”Objective:To evaluate the effect of irisin on the alveolar macrophage polarization in a rat model of ventilator-induced lung injury (VILI).Methods:Thirty SPF healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups (n n=10 each) using a random number table method: control group (group C), VILI group (group V) and irisin group (group I). The rats were mechanically ventilation (tidal volume 20 ml/kg, respiratory rate 80 times/min, inhaled oxygen concentration 21%, inspiratory/expiratory ratio 1∶2, positive end-expiratory pressure 0) for 4 h to develop VILI model.Group C kept spontaneous breathing for 4 h. Irisin 1 μg/kg was injected n via the tail vein at 30 min before tracheal intubation in group I, while the equal volume of normal saline was given instead in the other groups.The rats were sacrificed at 4 h of mechanical ventilation, the lung tissues were removed for examination of pathological changes which were scored and for determination of wet to dry weight ratio (W/D ratio), and bronchoalveolar lavage fluid (BALF) was collected for determination of concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and IL-10 (by enzyme-linked immunosorbent assay), expression of inducible nitric oxide synthase (iNOS), argininase 1 (Arg-1), and phosphorylated nuclear factor kappa B (p-NF-κB) p65 and p-NF-κB p50 in alveolar macrophages (by Western blot), and percentage of M1 and M2 alveolar macrophages and M1/M2 ratio (by flow cytometry).n Results:Compared with group C, the W/D ratio, lung injury score, and concentrations of IL-6, TNF-α and IL-10 in BALF were significantly increased, the expression of iNOS, Arg-1, p-NF-κB p65 and p-NF-κB p50 was up-regulated, and the percentage of M1 and M2 alveolar macrophages and M1/M2 ratio were increased in group V and group I (n P<0.05). Compared with group V, the W/D ratio, lung injury score, and concentrations of IL-6 and TNF-α in BALF were significantly decreased, the expression of iNOS and p-NF-κB p65 was down-regulated, the percentage of M1 alveolar macrophages and M1/M2 ratio were decreased (n P0.05).n Conclusions:The mechanism by which irisin reduces VILI may be related to inhibition of NF-κB signaling pathway activation and reduction of alveolar macrophage polarization to M1 phenotype in rats.