SMAD2 and pulmonary fibrosis: Inhibited pulmonary fibrosis and airway inflammation: the number of coughs, inflammatory cells, TGF-β1, p-Smad2/3/4, VEGFA, TNF-α, TLR4, MyD88, NF-κB, p-IKKβ↓; Smad7↑; inhibited pulmonary fibrosis