地塞米松对哮喘大鼠中性粒细胞激活肽-78和转化生长因子-β1表达的影响

Effects of dexamethasone on expressions of epithelial neutrophil activating protein-78 and transforming growth factor-beta 1 in neutrophil of asthma rats

目的探讨地塞米松对哮喘大鼠中性粒细胞（NEU）内皮中性粒细胞激活肽-78（ENA-78）和转化生长因子-β1（TGF-β1）表达的影响。方法30只SPF级雄性SD大鼠随机分为三组：哮喘组、健康对照组、地塞米松治疗组。以卵清白蛋白（OVA）致敏和激发制备大鼠哮喘模型，分离纯化血NEU，流式细胞仪测定血NEUENA-78的表达，免疫组织化学法测定血NEU和支气管组织中TGF-β1蛋白的表达水平。结果地塞米松治疗组NEUENA-78的平均荧光强度[（71．82±8．87）MFI]显著低于哮喘组且高于健康对照组（均P〈0．01）。地塞米松治疗组NEU和支气管的TGF—β1蛋白的平均吸光度A值[依次为（0．173±0．014），（0．202±0．019）A值]显著低于哮喘组且高于健康对照组（均P〈0．01）。NEUENA-78的表达水平与支气管肺泡灌洗液炎性细胞总数呈显著正相关（n=29，1=0．762，P〈0．01）。结论糖皮质激素（地塞米松）治疗哮喘大鼠的部分机制可能是通过抑制NEU分泌ENA-78和TGF-β1蛋白，从而抑制哮喘大鼠气道炎性。

Objective To investigate the effects of dexamethasone on expressions of epithelial neutrophil activating protein-78 （ ENA-78 ） and transforming growth factor- beta 1 （ TGF-β1 ） in neutrophil of asthma rats. Methods Thirty male SD rats were randomly divided into three groups on average, including asthma group, control group and dexamethasone treated group. In this experiment, the rat model of asthma were established by sentization and challenge with ovalbumin. Blood neutrophil were isolated and purified. The expression of ENA-78 was detected by flow cytometry. The expression of TGF-β1 was detected by immunohistochemical method in blood neutrophil and branchiat wall. Results Expression of ENA-78 in blood neutrophil in dexamethasone treated group （71.82 ± 8. 87 mean fluorescence intensity）was lower than that in asthma group,but higher than that in control group（ all P 〈0. 01 ）. And expressions of TGF-β1 protein in dexamethasone treated group （0. 173 ± 0. 014,0. 202 ± 0. 019 optical density, respectively） was lower than that in asthma group （ all P 〈 0.01 ）, but higher than that in control group（ all P 〈 0. 01 ）. There were significant positive correlation between ENA-78 expression at blood neutrophil and numbers of total inflammation cells in bronchoatveolar lavage fluid （ n = 29, γ= 0. 762, P 〈 0. 01 ）. Conclusion The beneficial effect of glucocorti- coid（dexamethasone） on airway inflammation in asthma rats could be at least in part due to their direct inhibitory effect on ENA-78 and TGF-β1 protein generation by neutrophil.