The effects of ambroxol hydrochloride on transforming growth factor-β_1 and γ-glutamylcysteine synthetase in lung of smoking rats

Objective To investigate the effects of Ambroxol hydrochloride on the levels of transforming growth factor-β1 (TGF-β1) and γ-glutamylcysteine synthetase (γ-GCS) in smoking rats, and to explore the role of ambroxol as an antioxidant in treatment of COPD. Methods Wistar rats were exposed to cigarette smoke for construction of COPD models. In a group of rats, ambroxol galvage were given for 8 consecutive weeks starting from week 4. Data on expiratory airway resistance, lung compliance, expression of TGF-β1 and γ-GCS in airway endothelial cells and alveolar macrophages were compared among the normal controls, untreated models (smoking group) and ambroxol-treated rats (ambroxol group). Results The expiratory airway resistance was increased and lung compliance decreased significantly in the smoking group and ambroxol group, while the ambroxol group showed lower airway resistance and higher lung compliance compared with the smoking group (P0.05). The level of TGF-β1 and γ-GCS expressions in smoking group and ambroxol group was obviously increased compared with normal controls (P0.01). The ambroxol group showed lower level of TGF-β1 mRNA and proteins (P0.05), similar levels of γ-GCS protein in airway endothelial cell and γ-GCS mRNA in alveolar macrophages but higher level of γ-GCS protein in alveolar macrophages as compared with the smoking group (P0.05). Conclusion In smoking rats, Ambroxol may result in improved lung function, decreased expression of TGF-β1 and increased level of γ-GCS protein in alveolar macrophage, suggesting its role as antioxidant in treatment of COPD.