Protective effect of amygdalin on epithelial–mesenchymal transformation in experimental chronic obstructive pulmonary disease mice

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory pulmonary disease characterized by continuous, progressive limitation of airflow. Airway remodelling, which is correlated with epithelial–mesenchymal transitions (EMTs), is a typical pathophysiological change of COPD. Amygdalin, an active ingredient in the traditional Chinese medicine bitter almond with extensive pharmacological effects, was shown to inhibit tissue fibrosis in recent studies. In this study, a human bronchial epithelial cell line (BEAS‐2B) and mice were exposed to cigarette smoke, and EMT levels were investigated after treatment with different concentrations of amygdalin. Morphology was assessed by immunohistochemical staining. Evaluation of the expression of TGF‐β1, smad2/3, and p‐smad2/3 in lung tissue was conducted out via ELISA, Western blot, and real‐time PCR. The results showed that E‐cadherin expression was significantly increased, whereas vimentin, TGF‐β1, and phosphorylated smad2/3 (p‐smad2/3) expression was markedly decreased in the amygdalin‐treated groups compared with the model group. Therefore, our study demonstrated a protective role of amygdalin in the murine EMT process after COPD.