慢性阻塞性肺疾病小气道NOX4、TGF-β的表达与气道重塑的关系

摘要

目的:探讨烟酰胺腺嘌呤二核苷酸磷酸氧化酶4(NOX4)、转化生长因子β(TGF-β)的表达与慢性阻塞性肺疾病(COPD)小气道重塑的关系.方法:收集55例因肺部肿瘤行肺叶切除的患者,根据临床资料及术前肺功能分为COPD组(36例)及对照组(19例),术中留取病变远端正常的肺组织标本.采用HE染色观察COPD组及对照组小气道形态学变化;采用免疫组织化学法、免疫荧光双染法及免疫印迹检测小气道组织NOX4、TGF-β、α-SMA及胶原蛋白Ⅳ的表达情况,并分析其与肺功能气流受限严重程度的相关性.结果:①COPD组小气道平滑肌厚度占气道外径的百分比(WT％)、小气道平滑肌面积占支气管断面面积百分比(WA％)明显高于对照组(P＜0.05);WT％和WA％在不同肺功能分级的COPD组间比较,差别均有统计学意义(P＜0.05).②COPD组上皮细胞增生明显,部分上皮细胞表达间质细胞表型α-SMA及胶原蛋白Ⅳ.COPD组上皮细胞α-SMA及Ⅳ型胶原蛋白免疫染色强度明显强于对照组(P＜0.05).③NOX4在COPD组小气道平滑肌及上皮细胞中的表达明显高于对照组(P＜0.05),NOX4的表达在不同肺功能分级的COPD组间比较,差别均有统计学意义(P＜0.05).④TGF-β在COPD组小气道平滑肌细胞及气道上皮细胞的表达均高于对照组(P＜0.05).⑤COPD小气道平滑肌WT％、WA％与肺功能FEV1％ pred、FEV1/FVC％呈负相关(P＜0.05);小气道平滑肌细胞NOX4的表达与肺功能FEV1％ pred、FEV1/FVC％呈负相关(P＜0.05).结论:COPD存在以小气道平滑肌增生及细胞外基质沉积为主要表现的气道重塑,且气道重塑的程度与气流受限严重程度呈正相关,COPD小气道上皮细胞和小气道平滑肌细胞表达NOX4、α-SMA和TGF-β明显增高,NOX4、α-SMA、TGF-β的表达与COPD气流受限严重程度呈负相关,提示TGF-β、NOX4信号机制可能参与COPD气道重塑的发生发展.%Objective:To investigate the role of nicotinamide adenine dinucleotide phosphate 4 (NADPH4,NOX4) and transforming growth factor-beta (TGF-β) involve in pathogenesis of airway remodeling in chronic obstructive pulmonary disease (COPD).Methods:Lung tissues from 36 COPD patients and 19 patients with normal lung function were enrolled in this study.The volume of airway smooth muscle (ASM)mass was evaluated.The expressions of NOX4,collagen Ⅳ (Col Ⅳ) and TGF-β were tested by a semi-quantitative morphological and/ or immunohistochemistry staining method and Western blot,and their correlations with pulmonary functions were analyzed.Results:①Index of the percentage of the thickness of ASM/external diameter of small airway (WT％) and the percentage of the area of ASM/transverse area of small airway (WA％) were significantly higher in the COPD group than those in controls(P ＜ 0.05).②In COPD patients,epithelial cells metaplasia were found and α-SMA and Col Ⅳ were expressed in a part of epithelial cells.The expressions of α-small muscle actin (α-SMA) and Col Ⅰ were increased in COPD patients in comparison with the patients without obstructive airway disorders(P ＜0.05).③The expression of NOX4 in ASM and epithelial cells of COPD patients was significantly higher in comparison with the patients without COPD.The expression of NOX4 in ASM of small airway were statistically different among different COPD grade (P ＜ 0.05).Correlation analysis demonstrated that the level of NOX4 protein in ASM of small airway was inversely associated with pulmonary functions.④The expression of TGF-β in COPD was significantly higher than that in patients without COPD.⑤ Correlation analysis demonstrated that the level of NOX4 protein in ASM of small airway,WT％ and WA％ were inversely associated with pulmonary functions.Conclusion:①The airway remodeling of COPD is characterized by increasing hyperplasia of small airway smooth muscle.②Remodeling of airway smooth muscle associats with severity of airflow limitation in COPD patients.③The expressions of NOX4,TGF-β and α-SMA in COPD epithelial cells and small airway smooth muscle cells are significantly enhanced.The expressions of NOX4,α-SMA and TGF-β are positively correlated with the severity of chronic obstructive pulmonary air flow,suggesting that TGF-β and NOX4 signaling may be involved in the development of chronic obstructive pulmonary disease airway remodeling.