Oridonin Inhibits Myofibroblast Differentiation and Bleomycin-induced Pulmonary Fibrosis by Regulating Transforming Growth Factor β (TGFβ)/Smad Pathway.

BACKGROUND Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unknow. etiology and a high mortality rate. Oridonin is a diterpenoid isolated from the Rabdosia rubesecens with diverse biological functions. However, whether oridonin possess potential protective activity on IPF is still unclear. MATERIAL AND METHODS The aim of the present study was to explore the therapeutic effects of oridonin on IPF. First, TGF-β1-induced MRC-5 cells were employed for the evaluation of inhibitory activity in vitro. Then, a bleomycin (BLM)-induced mice pulmonary fibrosis model was used to verify the activity of oridonin in vivo. Several pathological changes, including alveolar space collapse, emphysema, and infiltration of inflammatory cells, were observed in the BLM‑treated mice. RESULTS Oridonin could significantly inhibit the mRNA and protein expression levels of α-SMA and COL1A1 in TGF-β1-induced MRC-5 cells. Oridonin could attenuate pathological changes, including alveolar space collapse, emphysema, and infiltration of inflammatory cells induced by BLM. In addition, oridonin could significantly inhibit BLM-induced upregulation of α-SMA and COL1A1 and the phosphorylation of Smad2/3 in lung tissues of mice. CONCLUSIONS Oridonin could be used as a potential therapeutic agent in treatment for patients with IPF. The mechanisms of anti-fibrosis effect of oridonin might be inhibition of the TGF-β/Smad pathway.