RORγt在支气管哮喘小鼠肺组织中的表达及布地奈德对其抑制作用

RORγt expression in the pulmonary tissue of asthmatic mice and the inhibitory effects of budesonide

摘要:

目的：观察布地奈德（BUD）对支气管哮喘小鼠肺组织中Th17细胞的特异性转录因子RORγt表达的影响，探讨BUD治疗哮喘的机制。方法：采用卵清蛋白（OVA）致敏方法建立支气管哮喘小鼠模型；Balb/c雌性小鼠30只随机分为对照组、哮喘组、BUD组，每组各10只。采用酶联免疫吸附试验(ELISA)技术检测小鼠肺泡灌洗液（BALF）、血清中白细胞介素-17（IL-17）水平；对BALF中炎性细胞进行计数；苏木精-伊红（HE）染色评价各组小鼠气道炎症程度；逆转录聚合酶链反应（RT-PCR）方法检测肺组织中RORγt mRNA表达水平。结果：哮喘组小鼠BALF、血清中IL-17水平较对照组明显升高（P<0.01），BUD治疗后IL-17水平明显降低（P<0.01）。肺组织中RORγt mRNA在哮喘组较对照组明显升高（P<0.01），BUP治疗后RORγt mRNA水平明显降低（P<0.01）。哮喘组细胞总数、中性粒细胞数和嗜酸性粒细胞数均较对照组明显增多（P<0.01），BUD组细胞总数、中性粒细胞数和嗜酸性粒细胞数与哮喘组比较明显减少（P<0.01），与对照组比较差异无统计学意义。HE染色表明BUD治疗后气管炎性反应明显缓解。结论：哮喘小鼠RORγt表达水平和IL-17水平增高，导致哮喘小鼠的全身和局部炎症反应增强，可能是导致哮喘发生的机制之一。BUD可通过抑制RORγt和IL-17的表达水平，发挥其免疫抑制功能而起到治疗哮喘的作用。

Abstract:

OBJECTIVE: To study the effect of budesonide (BUD) on RORγt expression in the pulmonary tissue of asthmatic mice and mechanisms of BUD in the treatment of asthma. METHODS: Blab/c asthmatic mouse model was induced by ovalbumin (OVA). Thirty female mice were randomly divided into three groups: control, asthmatic and BUD-treated. IL-17 levels in bronchoalveolar lavage fluid (BALF) and serum were measured using ELISA. Total and differential cell counts in BALF were measured. Airway inflammation was evaluated by hematoxylin and eosin staining. IL-17 mRNA and RORγt mRNA expression were measured by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: RORγt mRNA and IL-l7 levels in the asthmatic group were significantly higher than in the control group (P<0.01). BUD treatment significantly decreased RORγt mRNA and IL-l7 levels compared with the asthmatic group (P<0.01). Compared with the control group, total, neutrophil and eosinophil cell count in BALF increased significantly in the asthmatic group (P<0.01). After BUD treatment, counts of total, neutrophil and eosinophil cells in BALF were significantly reduced (P<0.01) and were similar to in the control group. Inflammatory reactions in the respiratory tract were significantly alleviated in the BUD treated group. CONCLUSIONS: RORγt and IL-l7 levels in the pulmonary tissue of asthmatic mice increase and this may be associated with the pathogenesis of asthma. BUD can inhibit RORγt and IL-17 and thus reduces lung inflammation.