Análise biomecânica e perfil proteômico de células em resposta à absorção de luz vermelha

Abstract

Photobiomodulation (PBM) is a non-invasive technique for tissue repair whose underlying cellular mechanisms still lack full understanding. Biomechanical responses of six cell lines were investigated under red light (633 nm) with different irradiance and time parameters (25 and 50 mW/cm² for 10 and 20 minutes). The cells were grouped as follows: (i) L929 fibroblasts, HaCaT keratinocytes, and OFCOL II osteoblasts; and (ii) C2C12 myoblasts, MG-63 osteosarcoma, and RAW 264.7 macrophages. Additionally, an integrated proteomic analysis of the first group was conducted to characterize the effects of irradiation from the epidermis to bone tissue. Using atomic force microscopy (AFM) and mass spectrometry, it was observed that red light induced cell-type-specific viscoelastic changes. L929 fibroblasts showed increased fluidity, decreased stiffness, and enhanced motility, while HaCaT keratinocytes exhibited irradiance-dependent responses. In contrast, OFCOL II osteoblasts were relatively insensitive to the treatment. RAW 264.7 macrophages demonstrated pronounced stiffening under higher doses and durations, reflecting their immune function and rapid cytoskeletal remodeling. C2C12 myoblasts showed moderate stiffness, with a slight increase in elasticity at higher doses. In the MG-63 sample, an increase in elastic modulus and a reduction in fluidity were observed, suggesting a reinforcement of the cytoskeletal structure. Proteomic analysis identified key roles in immune regulation, ATP production, and stress response, linking these pathways to viscoelastic modulation, especially in fibroblasts. Remodeling of the F-actin network, with contributions from microtubules and intermediate filaments, was identified as the primary mechanism for the mechanical changes. Our findings clarify how red light absorption influences cellular viscoelasticity via cytoskeletal rearrangement, providing insights for optimizing PBM-based therapies in tissue regeneration.