Abstract

Background : Pulmonary fibrosis (PF) is a progressive interstitial lung disease with limited pharmacotherapy and frequent adverse effects, prompting safer multi-target options from traditional medicines. Purpose : To determine whether Huangqi Guizhi Wuwu Decoction (HGD) mitigates PF and to elucidate mechanisms. Study design : Integrated in vivo bleomycin (BLM) induced mouse PF models (preventive and therapeutic regimens) with in vitro TGF-β1 driven assays in human pulmonary fibroblasts (HPFs), NIH/3T3 cells and A549 epithelial cells; nintedanib served as a positive control. Methods : Evaluated lung histopathology (H&E, Masson), collagen accumulation, fibroblast activation and epithelial mesenchymal transition (EMT) markers; quantified TGF-β/Smad signaling (p-Smad2/3) and profiled pulmonary immune subsets (macrophages, DCs, MDSCs). Performed RNA-seq on TGF-β1-stimulated NIH/3T3 cells and network pharmacology analyses to prioritize pathways and targets, followed by immunoblotting and functional validation. Results : HGD attenuated BLM-induced lung injury and collagen deposition, suppressed fibroblast activation, reversed epithelial EMT, and reduced pulmonary accumulation of macrophages, DCs and MDSCs. HGD decreased p-Smad2/3 in lung tissues and fibroblasts. Transcriptomics plus target-network analysis highlighted cell-cycle pathways, with experimental data supporting their modulation consistent with anti-fibrotic activity. No overt toxicity was observed at the tested doses. Conclusion : HGD exerts multi-target anti-fibrotic effects in BLM-induced PF, associated with inhibition of canonical TGF-β/Smad signaling, rebalancing of the pulmonary immune microenvironment and modulation of cell-cycle, supporting further development of HGD as an adjunct strategy for PF.