细胞外基质重塑在大鼠慢性阻塞性肺病模型气流阻塞中的作用

The effect of extracellular matrix remodelling on the airflow obstruction in rat COPD models.

目的:制备大鼠慢性阻塞性肺病(COPD)模型,探讨气道细胞外基质(ECM)重塑的病理特点及其在气流阻塞中的作用,以及不同干预因素的影响。方法:熏香烟加气管注小量内毒素法建立大鼠 COPD 模型,观察气道重塑的病理特点,测定肺功能及血气,气道各层横截面积,支气管肺组织匀浆羟脯氨酸(Hy)含量;粘膜下成纤维细胞(Fb)、淋巴细胞及肺泡巨噬细胞计数;放免法测定血清中透明质酸、层粘连素含量。观察蛋白激酶 C 抑制剂 H7,氧自由基清除剂 N-乙酰半胱氨酸(NAC)和转化生长因子(TGF)-β单抗干预对大鼠模型气道重塑的影响。结果:所建模型的病理及病理生理学改变基本符合人类 COPD 特点,Ⅰ型胶原为主的 ECM 气道壁过度沉积;小支气管上皮层、平滑肌层截面积较对照组显著增大,三个干预组上述指标较模型组显著降低;模型组粘膜下Fb、淋巴细胞及肺泡巨噬细胞数较对照组显著增高,Fb 功能活跃。NAC 组及 TGF-β单抗组 Fb、三个干预组淋巴细胞及肺泡巨噬细胞数较模型组显著降低;模型组 Hy 含量较对照组显著增高,且分别与 FEV_(0.3)/FVC%呈显著负相关、与吸气及呼气阻力呈显著正相关,粘膜下 Fb 与 Hy 含量呈显著正相关,H7组 Hy 含量显著高于模型组,NAC 组和 TGF-β单抗组较模型组显著降低;血清层粘连素及透明质酸含量较对照组显著增高。结论:气道壁以Ⅰ型胶原为主的 ECM 过度沉积及 Fb 增生活跃是 COPD 气道重塑的主要病理改变之一;清除氧自由基和拮抗TGF-β均可减轻气道 ECM 重塑,抑制 PKC 不能减少气道壁胶原的沉积。

Objective:To study the characteristic of extracellular matirx (ECM) remodelling and its role in air- flow obstruction in COPD rat models,and to observe the effect of N-acetylcysteine (NAC),inhibitor of protein ki- nose C (H7) and TGF-β monocolonal antibody on regulation of the extracellular matrix remodelling of the airway wall.Methods.53 Wistar rats were randomly divided into 5 groups,normal control group,COPD rat model group,NAC group,H7 group and TGF-β monocolonal antibody group.Pathologic examination of airway and lung tissues,pulmonary function and blood gas analysis were performed.Fibroblasts and lymphocytes in bronchial walls and alveolar macrophages were counted.The area of epithelial layer,smooth muscle layer and lamina propria in bronchi were measured with image analyzer.The hydroxyproline of bronchial lung tissue homogenates were de- termined with biochemistry method.The serum levels of laminin (LN) and hyaluronic acid (HA) were determined with RIA method.Results;The changes in histopathology,pulmonary function and blood gases of the model group were similar to those of COPD patients.The collagen content,mainly type I collagen,in airway walls was signifi- cantly increased.The cross-sectional areas of epithelial layer and smooth muscle layer were also significantly in- creased than those in control group.All the above changes were significantly decreased in the drug treated group compared with that of model group.The numbers of fibroblasts,lymphocytes and alveolar maerophages in the model group were significantly increased than those of the control group,while that in the drug treated groups were significantly decreased than model group,except the number of fibroblasts in the H7 group.Lots of macro- phages had phagocytosed smoke granules.The hydroxyproline content in the model group was significantly in- creased than that of control group and was negatively correlated to FEV0.3/FVC,and positively correlated to air- flow resistance.The number of fibroblasts was also positively correlated to the level of hydroxyproline.The serum LN and PA levels of the model group were also significantly increased.Hydroxyproline were significantly de- creased in the NAC group and TGF-β monoclonal antibody group,while increased in H7 group,compared with the model group.Conclusion.Excessive deposition of ECM,mainly type I collagen,and proliferation of functionally activated fibroblasts are important pathological changes of airway remodelling.TGF-β monoclonal antibody and NAC can alleviate airway extracellular matrix remodeling.H7 can increase collagen deposition within airway wall.