Bufei huoxue capsule alleviates bleomycin-induced pulmonary fibrosis in mice via TGF-β1/Smad2/3 signaling

Abstract

Ethnopharmacological relevanceBufei huoxue (BFHX) is a Traditional Chinese Medicine formulation that consists of Astragalus Exscapus L, Paeonia Lactiflora Pall, and Psoralea Aphylla L. It can ameliorate collagen deposition and inhibit EMT. However, it remains unknown whether and how BFHX alleviates IPF. Aim of the studyOur work aimed to explore the therapeutic efficacy of BFHX on IPF and dissect the mechanisms involved. Materials and methodsA mouse model of IPF was induced by bleomycin. BFHX was administered on the first day of modeling and maintained for 21 days. Pulmonary fibrosis and inflammation were evaluated by micro-CT, lung histopathology, pulmonary function assessment, and cytokines in BALF. In addition, we examined the signaling molecules involved in EMT and ECM by immunofluorescence, western Blot, EdU, and MMP (Δψm) assays. ResultsBFHX alleviated lung parenchyma fibrosis as evidenced by Hematoxylin-eosin (H&E), Masson's trichrome staining, and micro-CT, and it improved lung function. In addition, BFHX treatment not only decreased the levels of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α), but also upregulated E-cadherin (E-Cad) and downregulated α-smooth muscle actin (α-SMA), collagen Ӏ (Col Ӏ), vimentin, and fibronectin (FN). Mechanistically, BFHX repressed TGF-β1–driven Smad2/3 phosphorylation, which, in turn, suppressed EMT and transition of fibroblasts to myofibroblasts in vivo and in vitro. ConclusionBFHX effectively reduces the occurrence of EMT and inhibits the production of ECM by inhibiting the TGF-β1/Smad2/3 signaling pathway, which provides a potential novel therapeutic strategy for IPF.