Inhibition airway remodeling and transforming growth factor-β1/Smad signaling pathway by astragalus extract in asthmatic mice

• Published in: International journal of molecular medicine 2012-04, Vol.29 (4), p.564-568
• Main Authors: QU, ZHENG-HAI, YANG, ZHAO-CHUAN, CHEN, LEI, LV, ZHI-DONG, YI, MING-JI, RAN, NI
• Format: Article
• Language: English
• Subjects: airway remodeling; asthma; astragalus plant; trans-forming growth factor-β1/Smad signaling pathway
• ISSN: 1107-3756; 1791-244X
• DOI: 10.3892/ijmm.2011.868

Airway remodeling is characterized by airway wall thickening, subepithelial fibrosis, increased smooth muscle mass, angiogenesis and increased mucous glands, which can lead to a chronic and obstinate asthma with pulmonary function depression. In the present study, we investigated whether the astragalus extract inhibits airway remodeling in a mouse asthma model and observed the effects of astragalus extract on the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway in ovalbumin-sensitized mice. Mice were sensitized and challenged by ovalbumin to establish a model of asthma. Treatments included the astragalus extract and budesonide. Lung tissues were obtained for hematoxylin and eosin staining and Periodic acid-Schiff staining after the final ovalbumin challenge. Levels of TGF-β1 were assessed by immunohistology and ELISA, levels of TGF-β1 mRNA were measured by RT-PCR, and levels of P-Smad2/3 and T-Smad2/3 were assessed by western blotting. Astragalus extract and budesonide reduced allergen-induced increases in the thickness of bronchial airway and mucous gland hypertrophy, goblet cell hyperplasia and collagen deposition. Levels of lung TGF-β1, TGF-β1 mRNA and P-Smad2/3 were significantly reduced in mice treated with astragalus extract and budesonide. Astragalus extract improved asthma airway remodeling by inhibiting the expression of the TGF-β1/Smad signaling pathway, and may be a potential drug for the treatment of patients with a severe asthma airway.