DCN and idiopathic pulmonary fibrosis: Immunohistochemical (IHC) staining of CD68 and CD206 in lung tissue and in vitro experiments on THP-1-induced M2 macrophage polarization and transforming growth factor-beta 1 (TGF-β1)-induced MRC-5 fibrosis indicated that MSC-DCN may mitigate lung inflammation by altering macrophage recruitment and polarization and inhibiting TGF-β1 expression to reduce fibrous hyperplasia and collagen deposition, thereby improving the treatment of BLM-induced IPF.