CP and pulmonary fibrosis: By reducing the levels of transforming growth factor-beta (TGF-β) and tumor necrosis factor-alpha (TNF-α), collagen type I, collagen type III, hydroxyproline and serum ceruloplasmin in lung tissues, MSC exosomes can regenerate epithelial and alveolar cells, reduce alveolar inflammation and inhibit the apoptosis of endothelial cells, as a result of the reduction of pulmonary fibrosis, and inflammation [18].