Abstract
Tracheal cartilage repair requires simultaneous restoration of a stable cartilage matrix, airway patency, and mechanical support, yet the regenerative state of implanted stem cells remains difficult to control. Here, we show that 940-nm photobiomodulation (PBM) enhances the chondrogenic competence of adipose-derived stem cells (ADSCs) within a defined dose window. Among the radiant exposures tested, 50 J/cm
2
most effectively promoted cell-cycle progression, cartilage-matrix formation and expression of SRY-box transcription factor 9, type II collagen, and aggrecan, while suppressing fibrotic, hypertrophic, and catabolic markers. These effects were not reproduced by a temperature-matched heat control. In 3-dimensional porous scaffolds, preconditioned ADSCs exhibited improved survival, spreading, matrix deposition, and mechanical performance. Mechanistically, 940-nm PBM remodeled mitochondrial architecture, membrane potential, respiration, cellular adenosine triphosphate content and redox status. Pathway perturbation implicated transient receptor potential vanilloid 1-associated Ca
2+
signaling, a redox-dependent component of Akt/glycogen synthase kinase 3β activation and SRY-box transcription factor 9 nuclear localization in the chondrogenic response. Preconditioning also preserved cartilage-associated gene expression under inflammatory challenge and altered macrophage-associated inflammatory marker profiles. In a rabbit tracheal cartilage defect model, constructs preconditioned at 50 J/cm
2
improved cartilage-like tissue formation, epithelial repopulation, lumen patency, and mechanical function. These findings support repeated 940-nm PBM conditioning as a controllable ex vivo strategy for enhancing ADSC chondrogenic competence and improving early tracheal cartilage repair across cellular and tissue scales.