克拉霉素对激素反应性通路中组蛋白去乙酰化酶2及糖皮质激素受体的影响
Effect of clarithromycin on expressions of HDAC2 and GR in smoke-exposed asthmatic mice

摘要：目的 观察克拉霉素对激素反应性通路中组蛋白去乙酰化酶2(HDAC2)及糖皮质激素受体(GR)的影响，探讨克拉霉素对烟雾暴露哮喘小鼠可能的治疗作用。方法 选择BALB/c小鼠作为研究对象，通过卵蛋白致敏激发建立哮喘模型组(OVA组)、烟雾暴露哮喘组(SEA组)以及哮喘接触烟雾暴露后通过克拉霉素治疗组(CAM组)，同时设立对照组平行比较。采用组织病理学检测各组小鼠肺组织炎症情况，并通过PCR检测肺组织中HDAC2 mRNA的表达情况和Western blot检测肺组织中HDAC2和GR蛋白的表达。结果 组织病理学观察OVA组和SEA组均存在肺组织气道炎症，其中SEA组纤毛被严重破坏，而CAM组炎症细胞浸润减弱。与CAM组相比，SEA组小鼠支气管肺泡灌洗液中IL-4和IL-8水平均显著提高(104.36±14.39 vs. 65.49±10.82、681.35±66.18 vs. 321.49±90.37，P=0.031、0.017)。CAM组HDAC2 mRNA表达显著高于SEA组(0.062±0.013 vs. 0.031±0.015，P=0.032)。Western blot检测结果显示，与CAM组相比，SEA组HDAC2蛋白(0.23±0.017 vs. 0.49±0.022，P=0.033)和GR蛋白(0.19±0.014 vs. 0.64±0.023，P=0.011)表达均显著降低。结论 克拉霉素能抑制烟雾暴露的哮喘小鼠气道炎症反应，作用机制可能通过与GR相结合，影响下游HDAC2基因表达有关。
ABSTRACT: Objective To explore the effects of clarithromycin on the expressions of histone deacetylase-2 (HDAC2) and glucocorticoid receptor (GR) of cigarette smoke-exposed asthmatic mice. Methods BALB/c mice were chosen to be the subjects of this study. They were raised to establish asthma model (OVA group); and mice in one asthma group were exposed to smoke (SEA group), one asthma group were treated with clarithromycin (CAM group) after smoke exposure. Control group mice were used as parallel comparison. The histopathological changes were studied to assess lung tissue inflammation. Cell counts in bronchoalveolar lavage fluid were also tested for airway inflammation. Histone deacelytase2 (HDAC2) activity of lung tissues was measured by qRT-PCR. HDAC2 and GR expressions in the lung tissue were detected by Western blot. Results Histopathologic observation showed massive infiltration of inflammatory cells in both OVA group and SEA group, while inflammation infiltration attenuated in CAM group. Compared with those in CAM group, the levels of IL-4 and IL-8 in bronchoalveolar lavage fluid of SEA group increased significantly (104.36±14.39 vs. 65.49±10.82, 681.35±66.18 vs. 321.49±90.37; P=0.031, 0.017). The expression of HDAC2 mRNA in CAM group was significantly higher than that in SEA group (0.062±0.013 vs. 0.031±0.015, P=0.032). The expressions of HDAC2 protein (0.23±0.017 vs. 0.49±0.022, P=0.033) and GR protein (0.19±0.014 vs. 0.64±0.023, P=0.011) were significantly lower in SEA group than in CAM group. Conclusion Clarithromycin could attenuate airway inflammation in smoke-exposed asthmatic mice. The mechanism of action may be related to the expression of HDAC2 gene in the lower reaches by combining with GR