成肌纤维细胞在哮喘气道重塑中的作用及地塞米松对其的影响

The role of myofibroblast in asthmatic airway remodeling and the effect of dexamethasone on it

目的:探讨成肌纤维细胞(MF)在哮喘气道重塑中的作用并观察地塞米松对其的影响。方法:SD大鼠30只,随机分为哮喘组(A组)、生理盐水对照组(C组)和地塞米松治疗组(D组),每组10只。利用卵白蛋白(OVA)/Al(OH)3致敏与OVA雾化吸入激发建立大鼠哮喘模型。免疫组化测定肺组织中支气管上皮下成肌纤维细胞的α-平滑肌肌动蛋白(α-SMA)表达含量,并使用图像分析技术进行积分光密度(IOD)定量分析测定。ELISA法测定支气管肺泡灌洗液(BALF)中TGF-β1和IFN-γ的浓度。结果:①定量分析测定的IOD值显示A组支气管上皮下MF的α-SMA表达量较C组显著增加(P<0.01),D组表达量较A组减少(P<0.05)。②ELISA法测定结果:A组BALF中TGF-β1浓度较C组显著升高(P<0.01),D组较A组浓度降低(P<0.01),但仍高于C组(P<0.05)。A组BALF中IFN-γ浓度较C组显著降低(P<0.01),D组较A组浓度高(P<0.01),但仍低于C组(P<0.05)。结论:MF在气道重塑形成中起重要作用。地塞米松可能通过减少TGF-β1,增加IFN-γ的产生,抑制MF增殖和表达,起到抗哮喘气道重塑的作用。

Objective： To explore the effect of myofibroblast（MF） on asthmatic airway remodeling and the effect of dexamethasone on it. Methods： In the experiment, thirty Sprague-Dawley （SD） rats were randomly divided into the asthma group （group A）, the sodium chloride control group （group C） and the dexamethasone group （group D）. There were ten rats in each group. The rats were sensitized with ovalbumin and Al（OH）3 before repeatedly exposed to aerosolized ovalbumin. The a -smooth muscle actin （ α -SMA） expressions of MFofbronchial subepithelium in lung tissue were assessed with immunohistochemistry. By image analysis technique, their integral optical density （IOD） were quantitatively analysed. The concentra-tion of TGF- β 1 and IFN- γ in bronchoalveolar lavage fluid （BALF） was measured by ELISA. Results： （1）Compared with group C, the IOD value by quantitative analysis showed that the expression of MF＇s α -SMA in bronchial subepithelium in group A was significantly increased （P〈0.01）, and the expression in group D was significantly decreased compared with group A （P〈0.05）. （2）The results of FLISA： The concentration of TGF- β 1 in BALF in group A was higher than that in group C （P〈0.01）, and the concentration of TGF- β 1 in BALF in group D was iower than that in group A （P〈0.01）, but still higher than that in group C （P〈0.05）. The concentration of IFN- γ in BALF in group A was lower than that in group C （P〈0.01）, and the concentration of IFN- γ in BALF in group D was higher than that in group A （P〈0.01）, but still lower than that in group C （P〈0.05）. Conclusion： MF plays an important role in the course of airway remodeling. Dexamethasone may decrease the concentration of TGF- β1 and increase the concentration of IFN- γ, then inhibit proliferation and expression of MF. So Dexamethasone may be an effective drug to inhibit asthmatic airway remodeling.