Decreased expression of human aquaporin-5 correlated with mucus overproduction in airways of chronic obstructive pulmonary disease

摘要

＜正＞ Aim:To investigate the relationship between aquaporin-5（AQP5）expression andmucus overproduction in the airways of Chinese patients with chronic obstruc-tive pulmonary disease（COPD）and the correlation with pulmonary functionchange.Methods:Bronchial tissues were obtained from fiberoptic bronchoscopyand bronchial biopsy in West China Hospital from April to July 2004.Twenty-fivepatients were diagnosed as COPD patients,and another 20 were diagnosed as thecontrol patients.The expressions ofAQP5,mucin 5AC（MUC5AC）,and mucin inbronchial tissues were detected by semiquantitative RT-PCR,in situ hybridization,and immunohistochemical and alcian blue-periodic acid-Schiff（AB-PAS）staining,respectively.Results:Compared with the control group,an attenuated expres-sion of AQP5 was detected throughout the bronchial tissues from patients withCOPD（P＜0.01）,but no difference existed in the lung tissues（P＞0.05）.Simultaneously,increased staining of MUC5AC and mucus in submucosal glandswere noted（P＜0.01,respectively）.Smoking attenuated the expressions of AQP5and increased the staining of MUC5AC and mucus in submucosal glands in theCOPD groups（P＜0.01）,while there were no significant differences observed in thecontrol group（P＞0.05）.The decreased expression of AQP5 mRNA was correlatedwith forced expiratory volume in 1 s（FEV1）/forced vital capacity（FVC）（r=0.60,P＜0.01）,FEV1% predicted value（r=0.60,P＜0.01）,maximal expiratory flow in 50%vital capacity(V50)% predicted value（r=0.55,P＜0.01）,and maximal expiratory flowin 25% vital capacity(V25)% predicted value（r=0.45,P＜0.01）.The decreasedexpression was negatively correlated with MUC5AC mRNA of the epitheliumairways（r=-0.45,P＜0.01）and the AB-PAS-stained area of submucosal glands（r=-0.61,P＜0.01）.The upregulation of MUC5AC mRNA correlated with the posi-tively AB-PAS-stained area of submucosal glands and correlated negativelywith FEV1/FVC（r=-0.53;P＜0.01）,FEV1% predicted value（r=-0.53;P＜0.01）,V50%predicted value（r=-0.48;P＜0.01）,and V25% predicted value（