Flavonoids in Resina Draconis protect against pulmonary fibrosis via the TGF-β1/NOTCH1 pathway

Background It is known that flavonoids in Resina Draconis (FRD) have anti-inflammatory and analgesic effects, but the function and mechanisms of FRD against pulmonary fibrosis remain unknown. Objective The study aimed to study the effect and mechanism of FRD on pulmonary fibrosis. Methods Pulmonary fibroblasts were isolated and identified. After treatment with transforming growth factor (TGF)-β1 and FRD-containing serum, expressions of TGF-β1, Jagged1, Notch1, alpha-smooth muscle actin, and collagen I were examined using real-time quantitative PCR and Western blot. Besides, the related proteins were verified in rats with bleomycin-induced pulmonary fibrosis. Results We successfully isolated and identified pulmonary fibroblasts and proved that FRD-containing serum inhibits proliferation and downregulates Notch1 expression in TGF-β1-induced fibroblasts. Moreover, our results indicate that FRD might alleviate pulmonary fibrosis via the Jagged1/Notch1 signaling pathways in vivo. Conclusion Flavonoids in Resina Draconis might play a key role in pulmonary fibrosis via critical pathways, especially the TGF-β1 and NOTCH1 signaling pathways.