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目的研究糖皮质激素对小鼠哮喘模型气道黏液过度分泌的作用及机制。方法将24只 BALB/c 小鼠随机分为对照组、哮喘组和哮喘+地塞米松组,每组8只。各组小鼠于末次激发24 h 后进行麻醉,留取不同标本,观察支气管肺泡灌洗液(BALF)中细胞总数和嗜酸性粒细胞数,AB-PAS 染色了解气道杯状细胞变化,用 RT-PCR 和免疫组织化学染色分别检测肺组织黏蛋白基因MUC5AC mRNA 和蛋白、白细胞介素4(IL-4)mRNA。结果与对照组相比,哮喘组 BALF 嗜酸性粒细胞和气道杯状细胞均明显增多,而哮喘+地塞米松组明显减少;哮喘组肺组织 MUC5AC mRNA(0.5341±0.0303)和蛋白(0.1906±0.0008)、IL-4 mRNA(0.6265±0.0932)均较对照组(分别为0.1994±0.0128、0.1194±0.0007和0.2389±0.0289)明显增加(P 均<0.01),哮喘+地塞米松组(分别为0.2729±0.0345、0.1456±0.0003和0.2424±0.0260)均明显高于哮喘组(P 均<0.05),但哮喘+地塞米松组 IL-4 mRNA 和对照组差异无统计学意义(P>0.05),MUC5AC mRNA和蛋白较对照组均明显降低(P 均<0.01)。结论糖皮质激素可减轻哮喘小鼠肺组织炎症,并可能通过下调MUC5AC 和 IL-4表达在气道黏液过度分泌中起治疗作用。
Objective To study the effect and mechanism of glucocorticoid on airway mucus hypersecretion in mouse asthma model. Methods Twenty-four BALB / c mice were randomly divided into control group, asthma group and asthma + dexamethasone group, with 8 mice in each group. The mice in each group were anesthetized 24 h after the last challenge, and different samples were taken to observe the total number of cells and the number of eosinophils in bronchoalveolar lavage fluid (BALF). The changes of goblet cells in the bronchoalveolar lavage fluid RT-PCR and immunohistochemical staining were used to detect MUC5AC mRNA and protein, interleukin-4 (IL-4) mRNA in lung tissues respectively. Results Compared with the control group, the number of eosinophils and airway goblet cells in asthmatic BALF significantly increased in asthmatic rats and decreased significantly in asthma + dexamethasone group. The levels of MUC5AC mRNA (0.5341 ± 0.0303) and protein (0.1906 ± 0.0008) ) And IL-4 mRNA (0.6265 ± 0.0932) in the asthma + dexamethasone group were significantly higher than those in the control group (0.1994 ± 0.0128,0.1194 ± 0.0007 and 0.2389 ± 0.0289, respectively) 0.0345,0.1456 ± 0.0003, and 0.2424 ± 0.0260) were significantly higher than those in the asthma group (P <0.05). However, there was no significant difference between the asthmatic + dexamethasone group and the control group (P> 0.05) And protein than the control group were significantly lower (P all <0.01). Conclusion Glucocorticoids can reduce lung inflammation in asthmatic mice and may play a therapeutic role in the airway mucus hypersecretion by downregulating the expression of MUC5AC and IL-4.