Inhibitory Effect of [beta]-Elemene on Human Airway Granulation Tissue in vivo and in vitro

Background: Recurrent airway granulation hyperplasia and scar formation make airway stenosis a clinical challenge. Therefore, a new approach for the treatment of airway stenosis is necessary. Objective: To explore the inhibitory effect of [beta]-elemene on the proliferation of fibroblasts and airway granulation. Methods: In vivo: (1) study of the effect of local [beta]-elemene injection by bronchoscopy. (2) During bronchoscopy, granulation tissues both before and after treatment were obtained. HE staining was performed and the result compared. In vitro: (1) human airway primary fibroblasts were purified and characterized. (2) Fibroblasts were treated with [beta]-elemene and normal saline (NS) and then examined by optical and electron microscopy. (3) Fibroblasts treated with [beta]-elemene or NS were assessed for viability by tetrazolium salt assay. (4) Apoptotic rates were determined by flow cytometry. Results: In vivo: (1) after local injection of [beta]- elemene, airway granulation tissue was reduced. (2) Granulation tissue was found to have less edema, and fibroblasts turned into mature fiber cells. In vitro: (1) human airway primary fibroblasts were successfully purified and cultured. (2) Compared with the control group, fibroblasts of the experimental group became clumped, the plasma granules were increased, and some fibroblasts lost their nucleus and organelles. (3) Compared with the control group, reduction of cell viability was detected with increased concentrations of [beta]-elemene. (4) With increased concentrations of [beta]-elemene, apoptotic rates of the fibroblasts were raised compared with the control group. Conclusions: [beta]-Elemene may induce apoptosis and necrosis of airway primary fibroblasts and inhibit the proliferation of fibroblasts and airway granulation. The results provide a new approach for the treatment of airway stenosis. Keywords: Granuloma, [beta]-Elemene, Human airway primary fibroblasts, Airway stenosis, Interventional bronchoscopic techniques