Preventive and curative effects of dicaffeoylquinic acid on early pulmonary fibrosis in mice

Objective: To explore the effect of dicaffeoylquinic acid (IBE5) on prevention and treatment of pulmonary fibrosis induced by bleomycin (BLM) in mice and its mechanism. Methods: Hydroxyproline content determination, imaging analysis, collagen I and III assay, α-smooth muscle actin (α-SMA) and matrix metalloproteinase 7 (MMP-7 ) immunohistochemistry were performed. Results: 1)Hydroxyproline content decreased in fibrotic lung tissue after administration of IBE5(P<0.05). 2)The number of pulmonary alveoli reduced, alveolus interstitium was thickened and collagen deposition and fibrosis were formed in lung tissue of BLM group. The break of pulmonary alveoli and extension of pulmonary fibrosis were decreased by use of IBE5 (P<0.05). 3)A lot of collagen I and III were synthesized in lung interstitium in BLM group and their quantity was reduced in IBE5 group (P<0.05). 4) In BLM group, α-SMA expression increased and located in myofibroblasts in fibrotic area, and MMP7 immunohistochemical signal was located in myofibroblasts also. They were decreased in IBE5 group(P<0.05). Conclusion: IBE5 plays a preventive and curative role in pulmonary fibrosis by inhibition of transformation of fibroblasts towards myofibroblasts and MMP7 expression. (authors)