Immunopathological characteristics and therapeutic effects of UC-MSCs in a pigeon breeder’s lung mouse model

• Established a comprehensive PBL mouse model that recapitulates both acute inflammatory and chronic fibrotic stages, providing a valuable tool for mechanistic studies and therapeutic evaluation. • Demonstrated that UC-MSCs, particularly at a high dose (1.6 × 10^6 cells), effectively treat non-fibrotic PBL by improving pulmonary function and reducing inflammation and fibrosis. • Identified distinct immunopathological phases in PBL progression: non-fibrotic (days 0–36), mild fibrosis (days 37–77), and severe fibrosis (day 78 onward), enabling stage-specific intervention. • UC-MSC therapy holds promise as a novel therapeutic strategy to delay fibrosis in PBL and other inflammation-induced lung fibrotic diseases, potentially preventing irreversible lung damage.