Protection of Qingfei Xieding prescription from idiopathic pulmonary fibrosis by regulating renin-angiotensin and ferroptosis in MLE-12 cells.

Idiopathic pulmonary fibrosis (IPF) is a lifelong lung disease, but there is no specific drug for treatment. Qingfei Xieding prescription (QF) is active in the treatment of lung diseases. More comprehensive mechanisms over how QF exhibits anti-pulmonary fibrosis need to be elucidated. TGF-β was used to construct a pulmonary fibrosis cell model <i>in vitro</i>. Bleomycin was applied to induce a lung tissue fibrosis model in mice <i>in vivo</i>. Flow cytometry was used to detect cellular ROS and lipid oxidation levels. Cell substructure was observed by Transmission Electron Microscopy. ELISA was used to determine the levels of inflammatory factors. HE staining, Masson staining and immunohistochemistry were performed to evaluate the degree of fibrosis. Western Blot assay was used to determine the protein expressions of different molecules. In TGF-β-exposed lung epithelial MLE-12 cell model, α-SMA and Collagen I were significantly elevated and cell viability was reduced. QF treatment restored the cell viability decreased by exogenous TGF-β. Ferroptosis inducer Erastin administration could reverse the beneficial effects such as lipid oxidation and ROS reduction caused by QF treatment. QF was proven to inhibit ferroptosis and alleviated the process of IPF by activating ACE2 signal axis. In bleomycin induced IPF mice model, QF altered lung coefficient, body weight and the expression of inflammatory factors, which were prevented by ferroptosis activator Erastin. QF was demonstrated to affect the ACE2-ERK signaling axis <i>in vivo</i>. QF alleviated idiopathic pulmonary fibrosis by regulating renin-angiotensin through blocking ferroptosis. This research offers evidence for the potentiality of QF in clinical application for IPF therapy.