Scutellarein inhibits BLM-mediated pulmonary fibrosis by affecting fibroblast differentiation, proliferation, and apoptosis

INTRODUCTION: Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible interstitial pulmonary disease that has a poor prognosis. Scutellarein, which is extracted from the traditional Chinese medicine Erigeron breviscapus, is used to treat a variety of diseases; however, the use of scutellarein for the treatment of pulmonary fibrosis and the related mechanisms of action have not been fully explored. METHODS: This study was conducted using a well-established mouse model of pulmonary fibrosis induced by bleomycin (BLM). The antifibrotic effects of scutellarein on histopathologic manifestations and fibrotic marker expression levels were examined. The effects of scutellarein on fibroblast differentiation, proliferation, and apoptosis and on related signaling pathways were next investigated to demonstrate the underlying mechanisms. RESULTS: In the present study, we found that scutellarein alleviated BLM-induced pulmonary fibrosis, as indicated by histopathologic manifestations and the expression levels of fibrotic markers. Further data demonstrated that the ability of fibroblasts to differentiate into myofibroblasts was attenuated in scutellarein-treated mice model. In addition, we obtained in vitro evidence that scutellarein inhibited fibroblast-to-myofibroblast differentiation by repressing TGF-β/Smad signaling, inhibited cellular proliferation by repressing PI3K/Akt signaling, and increased apoptosis of fibroblasts by affecting Bax/Bcl2 signaling. DISCUSSION: In general, scutellarein might exert therapeutic effects on pulmonary fibrosis by altering the differentiation, proliferation, and apoptosis of fibroblasts. Although scutellarein has been demonstrated to be safe in mice, further studies are required to investigate the efficacy of scutellarein in patients with IPF.