RÉSUMÉ
Pulmonary Fibrosis (PF) is a fatal disease in the interstitial lung associated with high mortality, morbidity, and poor prognosis. Transforming growth factor-ß1 (TGF-ß1) is a fibroblast-activating protein that promotes fibrous diseases. Herein, an inhalable system was first developed using milk exosomes (M-Exos) encapsulating siRNA against TGF-ß1 (MsiTGF-ß1), and their therapeutic potential for bleomycin (BLM)-induced PF was investigated. M-siTGF-ß1 was introduced into the lungs of mice with PF through nebulization. The collagen penetration effect and lysosomal escape ability were verified in vitro. Inhaled MsiTGF-ß1 notably alleviated inflammatory infiltration, attenuated extracellular matrix (ECM) deposition, and increased the survival rate of PF mice by 4.7-fold. M-siTGF-ß1 protected lung tissue from BLM toxicity by efficiently delivering specific siRNA to the lungs, leading to TGF-ß1 mRNA silencing and epithelial mesenchymal transition pathway inhibition. Therefore, M-siTGF-ß1 offers a promising avenue for therapeutic intervention in fibrosis-related disorders.