SMAD2 and asthma: In conclusion, our present study demonstrated that osthole could suppress cell apoptosis and EMT process in bronchial epithelium via MAPK and TGF-β1/smad2/3 signaling pathways, thereby alleviating airway epithelium injury and EMT-induced subepithelial fibrosis during the pathogenesis of airway remodeling in paediatric asthma.