Caracterización de la fotobiomodulación con luz roja en la proliferación y transferencia mitocondrial en células estromales mesenquimales humanas: un estudio in vitro

Abstract

Photobiomodulation (PBM) is a non-invasive therapy that modulates mitochondrial activity and tissue regeneration; however, its underlying mechanisms are not yet fully understood. Mesenchymal stromal cells (MSCs) are widely used in regenerative applications, but they exhibit limited survival and proliferative capacity in vivo, restricting their clinical efficacy. Although PBM has been shown to enhance MSC proliferation and influence mitochondrial dynamics , its effect on horizontal mitochondrial transfer, a key regenerative mechanism, remains largely unexplored. In this study, the effect of red LED PBM on proliferation and horizontal mitochondrial transfer in human WJ-MSCs was evaluated using an in vitro experimental design with energy doses of 0.9, 5.4, and 8.1 mJ/cm² (10, 60, and 90 s of irradiation). Proliferation was quantified by flow cytometry, and mitochondrial transfer was assessed through co-cultures analyzed by fluorescence microscopy. Results indicated that doses of 5.4 and 8.1 mJ/cm² significantly increased cell proliferation (1.15 and 1.25-fold, respectively) compared to the control. However, no significant changes in mitochondrial transfer frequency were observed for any of the evaluated doses. It was concluded that the 5.4 mJ/cm² treatment constitutes the optimal condition for stimulating WJ-MSC proliferation. Nonetheless, under the analyzed physical parameters, PBM does not promote horizontal mitochondrial transfer, suggesting that this mechanism requires additional stimuli or microenvironmental stress conditions to be enhanced.