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目的研究布地奈德(BUD)对支气管哮喘小鼠气道重塑及对 JAK1、信号转导子和转录激活子6(STAT6)表达的调控作用。方法将30只雌性 BALB/c 小鼠随机分为对照组、哮喘组和BUD 组。以鸡卵蛋白为过敏原致敏和激发动物,建立慢性哮喘气道重塑模型。对照组动物采用生理盐水致敏和激发动物,BUD 组在每次用过敏原激发前2 h 鼻腔滴入 BUD(1 mg/kg)。用 BUXCO 小鼠肺功能仪测定动物气道反应性,对肺组织切片行过碘酸雪夫(PAS)和 Masson 染色,就支气管周围炎细胞浸润及杯状细胞增殖进行评分,测定肺组织羟脯氨酸含量。应用免疫组化、免疫印迹及 RT-PCR方法分别检测 JAK1、STAT6、α-SMA 的蛋白及α-SMA mRNA 表达的变化。结果哮喘组动物气道反应性明显高于对照组,logPC100分别为0.62±0.78和1.88±0.34,P<0.01。BUD 组小鼠气道反应性低于哮喘组(1ogPC100为1.79±0.18,P<0.01)。与哮喘组相比,BUD 组气道上皮增生得到改善,上皮下胶原沉积减少,α-SMA 蛋白和 mRNA 表达也较哮喘组低。BUD 组黏液指数计分为(1.35±0.26)分,肺羟脯氨酸含量为(284±16)μg/100 mg,BALF 中 IL-4和 IL-13含量为(7.3±0.6)ng/L、(10.6±0.9)ng/L,与哮喘组比较差异有统计学意义(P<0.01)。STAT6主要表达于气道上皮,分布于细胞胞质、胞核。与对照组相比,哮喘组和 BUD 组的 STAT6分布未见明显变化。免疫印迹检测显示哮喘组的 JAK1和 STAT6蛋白表达均强于对照组,BUD 则能明显下调这两种信号蛋白的表达。相关分析表明,JAK1和 STAT6含量与气道 PAS 分数、α-SMA 蛋白表达及肺组织羟脯氨酸含量分别呈正相关,也与 BALF 中 IL-4和 IL-13水平呈正相关(均 P<0.05)。结论 BUD 抑制哮喘气道重塑。BUD可能通过下调 JAK1和 STAT6的表达,从而抑制了依赖于 JAK1/STAT6通路的气道重塑。
Objective To investigate the regulatory effect of budesonide (BUD) on airway remodeling and the expression of JAK1, signal transducers and activator of transcription 6 (STAT6) in bronchial asthmatic mice. Methods Thirty female BALB / c mice were randomly divided into control group, asthma group and BUD group. To chicken ovalbumin as an allergen sensitized and stimulated animals, the establishment of chronic asthma airway remodeling model. Animals in the control group were sensitized and challenged with saline, and BUD (1 mg / kg) was nasally instilled into the BUD group 2 h prior to each challenge with the allergen. The airway responsiveness of the animals was measured by the BUXCO mouse lung function instrument, the lung tissue sections were stained with PAS and Masson, and the perivascular inflammatory cell infiltration and goblet cell proliferation were scored. The levels of hydroxyproline Acid content. The expression of JAK1, STAT6 and α-SMA protein and α-SMA mRNA were detected by immunohistochemistry, Western blotting and RT-PCR respectively. Results The airway responsiveness of the asthmatic group was significantly higher than that of the control group. The logPC100 values were 0.62 ± 0.78 and 1.88 ± 0.34, respectively, P <0.01. The airway responsiveness of mice in BUD group was lower than that in asthma group (184 ± 0.18, P <0.01). Compared with the asthma group, the airway epithelial hyperplasia in BUD group was improved, the collagen deposition in the epithelium was decreased, and the expression of α-SMA protein and mRNA was also lower than those in the asthma group. The mucosal index of BUD group was (1.35 ± 0.26) points, the content of pulmonary hydroxyproline was (284 ± 16) μg / 100 mg, the level of IL-4 and IL-13 in BALF was (7.3 ± 0.6) ng / L , (10.6 ± 0.9) ng / L, respectively. There was significant difference between the two groups (P <0.01). STAT6 mainly expressed in the airway epithelium, located in the cytoplasm and nucleus. Compared with the control group, the STAT6 distribution in the asthma group and the BUD group showed no significant change. Immunoblotting showed that both JAK1 and STAT6 protein expression in asthma group was stronger than that in control group, while BUD significantly down-regulated the expression of both signaling proteins. Correlation analysis showed that the levels of JAK1 and STAT6 were positively correlated with airway PAS score, α-SMA protein expression and lung tissue hydroxyproline content, and positively correlated with IL-4 and IL-13 levels in BALF (all P <0.05 ). Conclusions BUD inhibits airway remodeling in asthma. BUD may inhibit airway remodeling that depends on JAK1 / STAT6 pathway by down-regulating the expression of JAK1 and STAT6.