ABSTRACT
BACKGROUND AND OBJECTIVE: Nuclear erythroid 2 p45-related factor-2 (Nrf2) is known to play important roles in airway disorders, whereas little has been investigated about its direct role in airway mucus hypersecretion. The aim of this study is to determine whether this factor could protect pulmonary epithelium and mouse airway from cigarette-induced mucus overproduction. METHODS: Using genetic approaches, the role of Nrf2 on cigarette smoking extracts (CSE) induced MUC5AC expression was investigated in lung A549 cells. Nrf2 deficiency mice were smoked for various periods, and the airway inflammation and mucus production was characterized. RESULTS: Acute smoking exposure induced expression of MUC5AC and Nrf2 in both A549 cells and mouse lungs. Genetic ablation of Nrf2 augmented, whereas overexpression of this molecule ameliorated CSE-induced expression of MUC5AC. Nrf2 knockout mice, after exposure to cigarette smoking, displayed enhanced airway inflammation and mucus production. CONCLUSION: Nrf2 negatively regulated smoking-induced mucus production in vitro and in vivo, suggesting therapeutic potentials of this factor in airway diseases with hypersecreted mucus.
Subject(s)
Lung/physiopathology , Mucus/drug effects , NF-E2-Related Factor 2/metabolism , Respiratory Mucosa/physiopathology , Smoking/adverse effects , Animals , Cell Line, Tumor , Gene Expression Regulation , Humans , Inflammation/etiology , Inflammation/metabolism , Mice , Mice, Inbred ICR , Mice, Knockout , Mucin 5AC/genetics , Mucin 5AC/metabolism , Mucus/metabolism , NF-E2-Related Factor 2/genetics , Reactive Oxygen Species/metabolismABSTRACT
AIM OF THE STUDY: Asthma is recognized as a common pulmonary disease throughout the world. To date, there has been a growing interest in herbal products in Traditional Chinese Medicine, which is considered to be effective to treat asthma. A Chinese herb Astragalus Membranaceus (AM) was found useful in treating allergic diseases. The purpose of this study is to determine whether this herbal injection could suppress allergic-induced AHR and mucus hypersecretion in allergic mice. MATERIALS AND METHODS: A mouse model of chronic asthma was used to investigate AM injection on the airway lesions in compared with glucocorticoids. The study was conducted on mice sensitized and challenged with ovalbumin and the whole body plethsmography was performed to assess AHR. The bronchoalveolar lavage (BAL), histopathology were examined. RESULTS: We found 28-day AM administration significantly decreased inflammatory infiltration and mucus secretion in the lung tissues of allergic mice. 28-day AM administration enhanced Ova-induced decreased IFN-gamma, and the Ova-induced elevations of IL-5 and IL-13 in BALF were prevented by 28-day injection. We also showed 28-day AM injection markedly suppressed increased AHR in allergic mice. CONCLUSIONS: Our results indicate Astragalus Membranaceus has a potential role in treating allergic asthma.
