• Intravenous (IV) administration of IMRCs outperforms intratracheal (IT) delivery in improving survival, body weight recovery, and reducing fibrosis scores in a bleomycin-induced mouse model of pulmonary fibrosis.
• Early and repeated (double) IV infusions of IMRCs significantly enhance therapeutic efficacy, improving lung function and promoting alveolar epithelial regeneration.
• IMRCs mitigate lung injury by suppressing macrophage infiltration via CD24, highlighting a novel immunomodulatory mechanism.
• These findings provide critical preclinical evidence for optimizing the route, timing, and frequency of IMRC administration, informing future clinical protocols for treating lung injury and fibrosis.