摘要目的 探讨S100A8、晚期糖基化终末产物受体(RAGE)、微囊蛋白1(Caveolin?1)在中性粒细胞性哮喘大鼠中的作用,以及罗红霉素干预其表达的可能机制.方法 采用随机数字表法将18只Brown Norway雄性大鼠分为对照组、哮喘组、罗红霉素组,每组6只.通过卵清白蛋白(OVA)和弗氏完全佐剂(FCA)腹腔注射联合致敏,OVA雾化激发构建大鼠哮喘模型,在每次激发前30 min,罗红霉素组大鼠予以罗红霉素30 mg/kg灌胃,对照组和哮喘组大鼠分别用等体积生理盐水代替.通过BALF中性粒细胞百分比(Neu%)及肺组织病理变化,确定哮喘模型的建立,检测各组大鼠BALF和血清中性粒细胞哮喘相关炎症因子表达,以及S100A8、RAGE和Caveolin?1蛋白含量的变化.结果 哮喘组大鼠BALF中Neu%明显高于对照组(P<0.01);罗红霉素组BALF中Neu%明显低于哮喘组(P<0.01).肺组织病理结果显示哮喘组大鼠支气管及血管周围、肺间质及肺泡腔内大量炎症细胞浸润,支气管壁及平滑肌明显增厚;罗红霉素组大鼠炎症表现及气道重塑情况较哮喘组减轻;对照组大鼠未见明显病理损害.哮喘组大鼠BALF和血清中炎症因子IL?6和IL?17水平明显高于对照组(均P<0.01),罗红霉素组IL?6和IL?17水平明显低于哮喘组(均P<0.05).哮喘组大鼠BALF和血清中S100A8和RAGE水平明显高于对照组[(20.6±4.4)比(7.1±2.0)ng/L、(885±118)比(462±102)ng/L和(14.2±1.7)比(7.6±1.8)ng/L、(774±166)比(406±69)ng/L](均P<0.05);罗红霉素组S100A8和RAGE水平明显低于哮喘组[(14.3±3.7)比(20.6±4.4)ng/L、(650±53)比(885±118)ng/L和(10.4±1.2)比(14.2± 1.7)ng/L、(537±81)比(774±166)ng/L](均P<0.05);同时哮喘组肺组织中Caveolin?1蛋白相对表达量明显低于对照组(P<0.01),罗红霉素组Caveolin?1蛋白相对表达量明显高于哮喘组(P<0.01).相关性分析结果显示S100A8和RAGE表达呈正相关(r=0.706,P<0.01);S100A8和Caveolin?1表达呈负相关(r=-0.775,P<0.01);Caveolin?1和RAGE表达呈负相关(r=-0.919,P<0.01).结论 S100A8和Caveolin?1可能通过RAGE在中性粒细胞性哮喘中发挥重要作用,罗红霉素可能部分通过这条通路发挥抗炎及抑制气道平滑肌重塑作用.

abstractsTo explore the role of S100A8, the receptor for advanced glycation endproducts (RAGE) and Caveolin?1 in neutrophilic asthmatic rats, and to further study the intervention of roxithromycin and the possible mechanisms. Methods Male Brown Norway rats were randomly assigned to a control group, an asthma group and a Roxithromycin group. The asthmatic rat model was established by intraperitoneal injection of ovalbumin (OVA) and Freund′s complete adjuvant (FCA) mixture, and aerosol inhalation of OVA. Rats in the Roxithromycin group were given roxithromycin injection 30 mg/kg 30 minutes before each challenge. Rats in the control and the asthma groups were replaced with equal volumes of saline, respectively. Bronchoalveolar lavage fluid (BALF) neutrophil percentage (Neu%) and pathological changes of pulmonary tissue (hematoxylin?eosin, HE staining) were measured to confirm the establishment of asthmatic models. The concentration of inflammatory cytokines and S100A8 were quantified by enzyme?linked immunosorbent assay (ELISA), and the expression of Caveolin?1 and RAGE at protein levels were detected by immunohistochemistry and Western blot. Results Neu% in BALF of the asthma group was significantly higher than those of the control group, and Neu% in the Roxithromycin group was lower than the asthma group (all P<0.01). Pulmonary histology revealed that there were a large number of inflammatory cells infiltrated in the bronchial and perivascular, pulmonary interstitial and alveolar spaces, and the bronchial wall and smooth muscles were thickened obviously in the asthma group. Rats in the Roxithromycin group showed milder inflammation and airway remodeling change than the asthma group. There was no obvious pathological damage in the control group. The concentration of IL?6 and IL?17 in BALF and serum of rats in the asthma group were significantly higher than those in the control group (P<0.01), and Roxithromycin inhibited the high expression of these cytokines (P<0.05). The expression of S100A8 and RAGE in the asthma group were significantly higher than those in the control group [(20.6 ± 4.4) vs (7.1 ± 2.0) ng/L; (885 ± 118) vs (462 ± 102) ng/L; (14.2 ± 1.7) vs (7.6 ± 1.8) ng/L; (774 ± 166) vs (406 ± 69) ng/L, all P<0.05], and Roxithromycin inhibited the high expression of these proteins [(14.3 ± 3.7) vs (20.6 ± 4.4) ng/L; (650 ± 53) vs (885 ± 118) ng/L; (10.4 ± 1.2) vs (14.2 ± 1.7) ng/L; (560 ± 64) vs (728 ± 72) ng/L] (all P<0.05). Meanwhile, the expression of Caveolin?1 in the asthma group was significantly lower than that in the control group (P<0.01), and Roxithromycin up?regulated its expression (P<0.01). Correlation analysis showed that there was a significantly positive correlation between the expression of S100A8 and RAGE (r=0.706, P<0.01), while there was a significantly negative correlation between the expression of S100A8 and Caveolin?1 (r=-0.775, P<0.01), and between the expression of Caveolin?1 and RAGE (r=-0.919, P<0.01). Conclusion S100A8 and Caveolin?1 may play an important role in neutrophilic asthma via RAGE, and Roxithromycin may exerts anti?inflammatory effects and inhibition of airway remodeling partly through this signaling pathway.