Efeito da fotobiomodulação à dexametasona sobre a viabilidade celular e expressão de marcadores inflamatórios por macrófagos ativados para o perfil M1

Abstract

Inflammation is essential for the body's defense, but its dysregulation can cause chronic diseases and tissue damage. Macrophages play a central role in this process, with the ability to polarize into M1 (pro-inflammatory) or M2 (anti-inflammatory) profiles. Photobiomodulation, a technique that uses low-intensity light, and dexamethasone, an anti-inflammatory glucocorticoid, have shown potential in inflammatory modulation. This study aimed to evaluate, in vitro, the effect of photobiomodulation (PBM), with or without the addition of DEXAmethasone (DEXA), on the modulation of inflammatory mediators and the cell viability of macrophages polarized to the M1 profile. J774 macrophages were used and divided into seven experimental groups: (1) Control, (2) M1, (3) M1 + FBM, (4) M1 + DEXA 2 μM, (5) M1 + DEXA 4 μM, (6) M1 + FBM + DEXA 2 μM, and (7) M1 + FBM + DEXA 4 μM. Macrophages were activated to the M1 profile using DMEM supplemented with 5% FBS, LPS (1 μg/mL), and IFN-γ (0.2 μg/mL), followed by incubation for 2 hours at 37°C with 5% CO2. In the groups treated with FBM, irradiation was performed with a 780 nm laser (AlGaAr, 70 mW, 17.5 J/cm², 1 J). DEXA (2 μM and 4 μM) was added to the corresponding groups, and the cells were incubated for 24 and 48 h. Cell viability was analyzed by MTT assay, and ELISA measured the levels of pro-inflammatory cytokines (TNF-α and IL-6). After 24 h, a significant increase in cell viability was observed in the group treated with the combination of PBM and 2 μM DEXA, compared to the groups treated with DEXA alone. On the other hand, the combination with 4 μM DEXA reduced total protein levels. After 48 h, the groups' cell viability differences became less pronounced. Regarding inflammatory modulation, DEXA treatment significantly reduced the levels of TNF-α and IL-6, although PBM partially mitigated these anti-inflammatory effects. The association of PBM with 2 μM DEXA demonstrated greater efficacy in inflammatory regulation and cell preservation, indicating a synergistic effect that enhances the transition to the M2 profile, essential for tissue repair. It is concluded that the combination of glucocorticoids, such as DEXA, with PBM represents a promising strategy for modulating the inflammatory microenvironment, contributing to the reduction of pro-inflammatory cytokines and stimulating tissue regeneration. Future studies are needed to investigate other inflammatory mediators, including anti-inflammatory cytokines, and to explore the clinical applicability of this approach in the treatment of inflammatory processes, both acute and chronic.