The effects of intragastric NAC (4 mg/kg, 3 times a day) on air-sacculitis and the expressions of TGF-β1, TNFα, and the platelet-derived growth factor (PDGF) were comparable with the effects of anti-fibrotic agent pirfenidone and corticosteroid prednisone, while the lung fibrosis score and caveolin-1 were more effectively influenced by pirfenidone [164]. Here, TGFB1 is linked to pulmonary fibrosis.