Background Chronic obstructive pulmonary disease （COPD） is usually complicated with mucus overproduction in airway. Recently the increased expression of the human calcium-activated chloride channel 1 （CaCC1） was found to play an important role in mucus overproduction in the asthmatic airways. To investigate the relationship of CaCC1 and mucus overproduction in the airway of Chinese patients with COPD, the expressions of CaCC1, MUC5AC and mucus in bronchial tissues were examined. Methods Bronchial tissues were obtained from fiberoptic bronchoscopy and bronchial biopsy in West China Hospital from April to July in 2004. Twenty-five patients were diagnosed as the patients with COPD overproduction, and other 20 were the control subjects. The expressions of CaCC1, MUC5AC and mucin in bronchial tissues were detected by reverse transcriptase-polymerase chain reaction （RT-PCR）, in situ hybridization with digoxigenin （DIG）-Iabeled RNA probe, immunohistochemical and alcian blue-periodic acid Schiff （AB-PAS） staining, respectively. Results Compared with the control group, the stronger expressions of CaCC1 were further detected throughout the bronchial tissues from patients with COPD （P〈0.01）. Furthermore, the stronger expressions of the CaCC1 mRNA were related to the severity of airflow obstruction. Samples from COPD showed a stronger staining for MUC5AC than those in control subjects （P〈0.01） and AB-PAS staining revealed more mucins in COPD patients＇ submucosal gland comparing with that in control subjects （P〈0.01）. Expression levels of the CaCC1 mRNA were respectively negatively correlated with the patients＇ forced expiratory volume in one second （FEV~） / forced vital capacity （FVC） data, FEV1% predicted data, V50% predicted data, V25% predicted data （r=-0.43, r=-0.43, r=-0.35, r=-0.36, P〈0.01, P〈0.01, P〈0.05, P〈0.05）. While the expression levels of the CaCC1 mRNA were well correlated with the expression levels of the MUC5AC mRNA of airway epithelium and the PAS
WANG Ke FENG Yu-ling WEN Fu-qiang CHEN Xue-rong OU Xue-mei XU Dan YANG Jie DENG Zhi-pin
Background Bleomycin-induced fibrosis is extensively used to model aspects of the pathogenesis of interstitial pulmonary fibrosis. This study aimed to determine the benefic effects and mechanisms of simvastatin on bleomycininduced pulmonary fibrosis in mice. Methods Bleomycin-induced pulmonary fibrosis mice were administered with simvastatin in different doses for 28 days. We measured inflammatory response, fibrogenic cytokines and profibrogenic markers in both bleomycin-stimulated and control lungs, and correlated these parameters with pulmonary fibrosis. Results Simvastatin attenuated the histopathological change of bleomycin-induced pulmonary fibrosis and prevented the increase of lung hydroxyproline content and collagen （Ⅰ and Ⅲ） mRNA expression induced by bleomycin. Moreover, simvastatin down-regulated the increased expression of transforming growth factor-β1 （TGF-β1） and connective tissue growth factor （CTGF） induced by bleomycin at both gene and protein levels. Simultaneously, the accumulation of neutrophils and lymphocytes and the increased production of tumor necrosis factor-a （TNF-α） in bronchial alveolar lavage fluid were inhibited by simvastatin in early inflammatory phase after bleomycin infusion. The higher dose of simvastatin was associated with a more significant reduction in these inflammatory and fibrotic parameters. Furthermore, the inactivation of p38, RhoA and Smad2/3 signaling pathways was observed during simvastatin administration. Conclusions Simvastatin attenuated bleomycin-induced pulmonary fibrosis, as indicated by decreases in Ashcroft score and lung collagen accumulation. The inhibitory effect of simvastatin on the progression of pulmonary fibrosis may be demonstrated by reducing inflammatory response and production of TGF-β1 and CTGR These findings indicate that simvastatin may be used in the treatment of pulmonary fibrosis.
OU Xue-mei FENG Yu-lin WEN Fu-qiang HUANG Xiang-yang XIAO Jun WANG Ke WANG Tao
Mucus hypersecretion is a distinguishing feature of chronic inflammation diseases, such as asthma,chronic bronchitis, bronchiectasis and cystic fibrosis Mucus hypersecretion leads to impairment of mucociliary clearance, abnormal bacterial plantation, mucus plug in the airway, and dysfunction of gas exchange.5 To block this vicious cycle, chronic inflammation in the airway must be controlled and mucus hypersecretion must be reduced.
