细胞外基质重塑在大鼠慢性阻塞性肺疾病模型气流阻塞中的作用

目的　制备大鼠慢性阻塞性肺疾病 (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　熏香烟加气管注入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 ;放射免疫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 (各为 2 1114 μm2 、16 0 6 1μm2 )与对照组 (各为 130 5 6 μm2 及 6 6 92 μm2 )比较 ,差异有显著性 (P均 <0 .0 0 1)。NAC组、H7组及TCF β单抗组上皮层截面积分别为 12 70 1μm2 、11836 μm2 及112 4 4 μm2 ;平滑肌层截面积分别为 70 5 1μm2 、6 4 2 6 μm2 及 6 4 2 0 μm2 ,与模型组比较差异有显著性(P均 <0 0 0 1)。模型组粘膜下Fb数为 13.6± 4 .2 ,对照组为 6 .8± 1.4 ,且功能活跃 ,淋巴细胞及肺泡巨噬细胞数亦显著增高。NAC组及TGF

The effect of extracellular matrix remodeling on airflow obstruction in a rat model of chronic obstructive pulmonary disease

OBJECTIVE: To study the nature of extracellular matirx (ECM) remodeling and its role in airflow obstruction in a rat model of chronic obstructive pulmonary disease (COPD), and to observe the role of nacetylcystein (NAC), protein kinase C (H(7)) and TGF-beta monocolonal antibody in the regulation of extracellular matrix remodeling in the airway wall. METHODS: Fifty-three Wistar rats were randomly divided into 5 groups: the healthy control group, the COPD model group, the NAC group, the H(7) group and the TGF-beta monocolonal antibody group. Pathologic study of the airway and lung tissue, lung function test and blood gas analysis were performed. Fibroblasts and lymphocytes of the bronchial wall and alveolar macrophages were counted. Areas of the epithelial layer, the smooth muscle layer and the lamina propria were measured by image analyzer. The level of hydroxyproline in bronchial and lung homogenates was determined by biochemistry method. The serum levels of laminin (LN) and hyaluronic acid (HA) were determined by RIA method. RESULTS: The changes in histopathology, lung function and blood gas in the animal model were similar to those in COPD patients. The collagen, mainly type I collagen, in airway walls was significantly increased. The areas of the epithelial layer (21 114 micro m(2)) and the smooth muscle layer (16 061 micro m(2)) were significantly increased in the COPD model as compared to the control group (13 056 micro m(2) and 6 692 micro m(2), respectively) (P < 0.01). In the drug intervention groups these parameters were significantly decreased compared to the control group. The numbers of fibroblasts (13.6 +/- 4.2), lymphocytes (35.6 +/- 6.4) and alveolar macrophages (14.8 +/- 1.1) in the model group, were significantly increased compared to the control group (6.8 +/- 1.4, 6.1 +/- 1.2 and 3.5 +/- 1.2, respectively) (P < 0.01, 0.001, 0.001), while in the drug intervention groups the cells were significantly decreased except for fibroblasts in the H(7) group. The hydroxyproline level of the model group (111.5 +/- 2.3) pg/ml was significantly increased as compared to the control group (47.8 +/- 9.7) pg/ml (P < 0.05) and was negatively correlated with FEV(0.3)/FVC (P < 0.001) and positively correlated with airflow resistance (P < 0.01). The number of fibroblasts was also positively correlated with the level of hydroxyproline (P < 0.001). The serum levels of LN (26 +/- 4) micro m/L and HA (19.4 +/- 1.4) micro g/L in the model group were significantly increased compared to the control group (15 +/- 3) micro g/L, and (10.9 +/- 2.9) micro g/L, respectively (P < 0.05). Hydroxyproline in the NAC group (83.1 +/- 41.7) pg/ml and the TGF-beta monoclonal antibody group (71.2 +/- 20.3) pg/ml was significantly decreased, while in the H(7) group (160.6 +/- 41.7) pg/ml it was significantly increased. CONCLUSION: Excessive deposition of ECM, mainly of type I collagen, and proliferation of functionally activated fibroblasts were important pathological changes in airway remodeling and the important causes of airflow obstruction. TGF-beta monoclonal antibody and NAC can modulate airway extracellular matrix remodeling. H(7) can increase collagen deposition in the airway wall but the underlining mechanisms need to be elucidated.