Nebulized mesenchymal stem cell-derived exosomes attenuate airway inflammation in a rat model of chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is one of the leading causes of death worldwide, and current treatments fail to significantly halt its progression. Exosomes derived from mesenchymal stem cells (MSCs-Exos) have demonstrated promising potential in treating COPD due to their anti-inflammatory and regenerative biological properties. In this study, we investigated the potential anti-inflammatory effects of bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exos) in a COPD rat model and the possible mechanisms by which they inhibit airway remodeling, as well as identifying the optimal dosage and administration route. Our results show that nebulized BMSC-Exos significantly improve lung function in COPD rats while reducing pulmonary inflammatory infiltration, bronchial mucus secretion, and collagen deposition. Moreover, BMSC-Exos treatment notably decreased the expression of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-1β, and the pro-fibrotic factor TGF-β1 in serum, bronchoalveolar lavage fluid (BALF), and lung tissue. The most pronounced therapeutic effect was observed at a low dose of exosomes. Furthermore, quantitative real-time PCR and immunohistochemical analyses revealed that nebulized BMSC-Exos significantly inhibited airway remodeling and epithelial–mesenchymal transition (EMT) by suppressing the Wnt/β-catenin signaling pathway. In conclusion, these findings indicate that nebulized BMSC-Exos offer a noninvasive therapeutic strategy for COPD by mitigating lung inflammation and airway remodeling through the suppression of abnormal Wnt/β-catenin pathway activation induced by cigarette smoke (CS) and lipopolysaccharide (LPS) in rats.