TGFB1 and stricture: For example, subglottic stenosis is the result of local fibrous repair after airway damage.[12] PFD is a kind of pyridinone compound with broad-spectrum anti-fibrosis effects and can prevent and reverse formation of fibrosis and scar, which has been confirmed in the treatment of pulmonary fibrosis and other fibrosis diseases.[13] PFD with the concentration of 200 to 1000 μg/mL can inhibit migration of basal cells isolated from keloid and expression of core EMT genes induced by TGF-β1.