基质金属蛋白酶及其抑制剂在哮喘气道重塑中的作用及止喘胶囊的干预

目的:探讨基质金属蛋白酶(matrix metalloproteinase, MMP)及其抑制剂(tissue inhibitor of metalloproteinase, TIMP)在支气管哮喘气道重塑中的可能作用以及止喘胶囊(补肾纳气法)对气道重塑的干预作用.方法:通过长期反复地给予致敏大鼠吸入不同浓度的卵蛋白,建立大鼠慢性哮喘气道重塑模型.分别在哮喘激发后第2、4、6、8周动态观察模型大鼠MMP/TIMP的表达情况.并在激发第8周观察中药组、西药组、中西医结合组的治疗效果.免疫组化技术检测气道壁MMP-9、TIMP-1以及Ⅰ型、Ⅲ型、Ⅴ型胶原蛋白表达,计算机图像分析显微测定气道壁厚度.结果:模型大鼠气道上皮损伤、脱落,嗜酸性粒细胞浸润;MMP-9在初始阶段表达上调,在后期下降;TIMP-1在整个过程中呈持续上升状态.模型组气道壁厚度、胶原沉积、TIMP-1表达明显高于正常对照组(P<0.05),中药组、西药组、中西医结合组的气道壁厚度、胶原沉积、TIMP-1表达明显低于模型组(P<0.05),其中中西医结合组与其他组比较,疗效最佳(P<0.05).结论:MMP/TIMP比例失衡,比值下降,是哮喘气道重塑的一个重要因素.TIMP-1过度表达与纤维化相关;止喘胶囊能显著抑制TIMP-1的高表达,减少气道壁厚度和胶原沉积,从而阻抑气道重塑的发生和发展,与地塞米松有协同作用.

Function of MMP/TIMP on airway remodeling of bronchial asthma and treating effects of Zhichuan Capsule

OBJECTIVE: To explore the mechanism of the bronchial asthma and to study the treating effects of Zhichuan Capsule on the airway remodeling of asthmatic model rats. METHODS: The rat model was established by being sensitized and activated with different density of ovalbumin through prolonged and repeated exposure for 8 weeks. The rats were randomly divided into model group, Zhichuan Capsule treated group, dexameson treated group, and Zhichuan Capsule and dexameson treated group. Another group of normal rats were taken as control. General histological changes were observed by hematoxylin and eosin stained sections. Being standardized by internal perimeter (Pi), the wall thickness (d), internal area (Ai), outer area (Ao) and wall area (WA) of the airway were quantified by computer-assisted image analysis system. The express of MMP-9, TIMP-1, Col I, Col III and ColV in the airway were examined by immunocytochemical methods. During the course of airway remodeling, the dynamic changes of model rats were observed at different time points (2, 4, 6 and 8 weeks after the activating). Statistical comparison was performed by ANOVA followed by Fisher LSD test. RESULTS: (1) Histologic examination showed eosinophil infiltration within the airway walls, epithelial damage, excessive mucus in the lumen and edema in the submucosa of the airways in model rats, and that the collagen deposition increased accompanied by increasing of TIMP-1. In the model rats, MMP-9 increased at the time point of 2 weeks, but it decreased in the late stage (8 weeks after activating) of airway remodeling. And the level of TIMP-1 was far higher than MMP-9 at the time point of 8 weeks. (2) Zhichuan Capsule could down-regulate the level of TIMP-1 in the airway wall, as well as the thickness of airway wall and the collagen deposition. And there were progressing effects when it was used together with dexameson. CONCLUSION: (1) The early increase of MMP-9 is a key point to start remodeling; and the increase of TIMP-1 in the late stage, which inhibits collagenase activity, may play an important role in developing airway fibrosis. Imbalance between MMP-9 and TIMP-1 is a marker of airway remodeling. (2) Zhichuan Capsule can decrease the deposition of collagen and suppress the airway remodeling by inhibiting the TIMP-1 expression.