骨桥蛋白在哮喘小鼠肺组织中的表达及地塞米松的干预作用

Effect of dexamethasone on osteopontin expression in the lung tissue of asthmatic mice

目的探讨哮喘气道炎症与骨桥蛋白(OPN)表达的相关性,以及地塞米松(DXM)对OPN表达的影响。方法 50只小鼠随机分为正常对照组、不同程度哮喘组(卵清蛋白OVA激发1周和2周组)及DXM治疗1周和2周组,每组10只;OVA致敏、激发建立急性哮喘模型;苏木精-伊红染色观察各组小鼠气道炎症情况;ELISA法检测血清OVA-s Ig E水平;免疫组化和Westernblot法分别定位和定量分析肺组织OPN表达;Real-timePCR检测肺组织OPNm RNA水平。结果哮喘组气道病理学改变较对照组和DXM组明显,且OVA激发2周哮喘组改变较激发1周组明显。哮喘组血清OVA-s Ig E水平较对照组和DXM组明显升高(P<0.01);且OVA激发2周组高于激发1周组(P<0.01)。Westernblot和Real-timePCR结果显示哮喘组OPN及OPNm RNA表达较对照组和DXM组均显著升高(P<0.01);且OVA激发2周组的表达水平明显高于激发1周组(P<0.01)。结论 OPN可能是哮喘发病机制中的重要因素,哮喘气道炎症越重,OPN表达水平可能越高;DXM可能通过抑制OPN的表达来减轻哮喘炎症。

Objective To study the correlation between airway inflammation and osteopontin （OPN） level in the lung tissue, and to study the effect of dexamethasone （DXM） on OPN expression. Methods Fifty mice were randomly divided into 5 groups： normal control, ovalbumin （OVA）-challenged asthma groups （OVA inhalation for 1 week or 2 weeks） and DXM-treated asthma groups （DXM treatment for 1 week or 2 weeks）. The mice were sensitized and challenged with OVA to prepare mouse model of acute asthma. Alterations of airway inflammation were observed by haematoxylin-eosin staining. Serum level of OVA-sIgE was evaluated using ELISA. OPN expression in the lung tissue was located and measured by immunohistochemistry and Western blot respectively. OPN mRNA level in the lung tissue was detected by real-time PCR. Results The asthma groups showed more pathological changes in the airway than the normal control and the DXM-treated groups. Compared with the OVA-challenged 1 week group, the pathological alterations increased in the OVA-challenged 2 weeks group. The level of OVA-sIgE in serum increased in the asthma groups compared with the control and the DXM groups （P〈0.01）. Serum OVA-slgE sevel increased more significantly in the OVA-challenged 2 weeks group compared with the OVA-challenged 1 week group （P〈0.01）. OPN protein and mRNA levels were significantly raised in the asthma groups compared with the normal control and the DXM groups （P〈0.01）, and both levels increased more significantly in the OVA-challenged 2 weeks group compared with the OVA- challenged 1 week group （P〈0.01）. Conclusions The increased OPN expression in the lung tissue is associated with more severe airway inflammation in asthmatic mice, suggesting that OPN may play an important role in the pathogenesis of asthma. DXM can alleviate airway inflammation possibly by inhibiting OPN production.