肌动蛋白和转化生长因子-β1在大鼠试验性肺气肿发生中的作用

目的　观察大鼠小气道上皮细胞肌动蛋白和转化生长因子 (TGF) β1在呼吸道上皮损伤修复及肺气肿发生中的作用。方法　将Wistar大鼠随机分为 2组 :吸烟加肺炎克雷伯杆菌感染组 (SI组 )和对照组 (C组 )。SI组应用吸烟加反复肺炎克雷伯杆菌感染法建立大鼠慢性阻塞性肺疾病(COPD)模型 ,C组动物不吸烟不染菌。透射电镜和光镜观察肺组织病理学改变。对各组动物进行动脉血氧分压 (PaO2 )、动脉血二氧化碳分压 (PaCO2 )和右心室收缩压 (RVSP)测定。免疫组织化学链霉素抗生物素蛋白 过氧化物酶 (SP)法检测各组大鼠小气道上皮细胞肌动蛋白和TGF β1表达的变化。结果　第 16周SI组大鼠与C组比较 ,小气道炎症反应明显 ,细支气管壁明显增厚 (P <0 0 5 ) ,内径与外径比明显降低 (P <0 0 5 ) ,并于 16周形成明显的肺气肿 ,肺腺泡内小动脉肌化明显 (P <0 0 5 )。SI组动物第 8周和第 16周PaO2 比C组明显降低 (P <0 0 5 ) ,而RVSP比C组明显升高 (P <0 0 5 )。C组大鼠小气道上皮细胞肌动蛋白表达较弱 [吸光度值 (A值 )为 0 0 9± 0 0 3],第 4周和第 8周 ,SI组小气道上皮细胞肌动蛋白阳性表达明显增强 (A值分别为 0 2 4± 0 0 6和 0 2 5± 0 0 5 ,P <0 0 5 )。C组大鼠肺组织TGF β1为阴性 ,SI组大鼠第 2、4、8

Changes of the actin and transforming growth factor-beta1 expression in the small airways of the rat with chronic obstructive lung disease

OBJECTIVE: To study the roles of actin and transforming growth factor (TGF)-beta(1) in the injury repair and the development of emphysema. METHODS: Wistar rats were randomly divided into two groups: the smoking and infection group (group SI) and the control group (group C). The rats of group SI received smoking irritation accompanying with repeated intranasal infection. Subgroups of the experimental animals were killed in the 2nd, 4th, 8th and 16th weeks respectively. The morphological changes of lungs were compared and PaO(2), PaCO(2) as well as the right ventricular systolic pressure (RVSP) were analysed. The lung sections were stained with immunohistochemistry for actin and TGF-beta(1). RESULTS: In comparison with animals of group C, thickening of the bronchiolar walls, narrowing of bronchiolar lumens, and area of emphysema were much severe in animals of group SI (P < 0.05). The muscularization of intra-alveolar arteries in group SI in the 16th week was apparent in comparing with that in group C (P < 0.05). PaO(2) values in group SI were significantly decreased, and RVSP values in group SI were significantly increased in the 8th and 16th week (P < 0.05). Actin expression was increased in animals of group SI in the 4th and 8th week (0.24 +/- 0.06 and 0.25 +/- 0.05) in comparing with that of group C (0.09 +/- 0.03) (P < 0.05). Animals of group SI showed a significant increase of TGF-beta(1) in lung tissue in different periods as mentioned in above (33.33 +/- 12.11, 45.71 +/- 15.12, 71.43 +/- 16.76 and 86.25 +/- 20.66 respectively). CONCLUSIONS: The increased expression of actin and TGF-beta(1) protein in small airways induced by smoking irritation and Klebsiella Pneumoniae may interfere with the repair response, and contributes to the development of emphysema.