Speaker
Description
Photobiomodulation (PBM) refers to the application of low-level light at specific wavelengths delivered either continuously or in pulses with low and constant energy densities in order to modulate cellular activity. This study investigated the influence of PBM at 525 nm (green), 825 nm (near-infrared; NIR) and a combination wavelength of both on adipose-derived stem cell (ADSC) using assays which assess cellular parameters such as proliferation, viability, mitochondrial function, extracellular matrix (ECM) production, migration and differentiation towards a smooth muscle cell (SMC) in the presence of growth factors like retinoic acid (RA) and transforming growth factor-β (TGF-β). ADSCs were exposed to fluences of 5 J/cm² and 10 J/cm² and assessed using metabolic (ATP), cytotoxicity (LDH), Giemsa for morphology; mitochondrial membrane potential (MMP), collagen quantification, migration analysis and immunofluorescence staining of stemness and SMC associated markers. Morphological analysis demonstrated that ADSCs initially maintained a typical spindle-shaped morphology across all experimental groups. However, fluence-dependent PBM effects became evident over time. Cultures exposed to 5 J/cm² maintained higher cell density and proliferation, whereas 10 J/cm² groups showed sparser cultures and reduced growth, consistent with the biphasic Arndt-Schulz response. ATP analysis supported this trend with lower fluence groups demonstrating enhanced metabolic activity by day 7, while higher fluence groups showed reduced proliferation. LDH levels remained low across all PBM-treated groups, confirming the absence of cytotoxic effects. Mitochondrial analysis indicated a generally stable MMP values during early stages with increased levels at later stages suggesting mitochondrial adaptation during differentiation. Collagen production showed an early increase followed by a decline at later time points, suggestive of ECM remodelling during cellular maturation. Migration analysis revealed differences in cell motility between treatment groups, indicating functional variations associated with PBM exposure. Immunofluorescence confirmed the progressive expression of smooth muscle associated markers including smooth muscle α actin, desmin, calponin and SMMHC during the experimental period. Collectively, these findings demonstrate that PBM modulates ADSC behaviour in a fluence-dependent fashion and may support smooth muscle lineage development under inductive culture conditions further highlighting the potential role of PBM in regenerative medicine applications.
