Efeito agudo da fotobiomodulação associada ao campo magnéticoestático em células musculares C2C12 expostas ao peróxido de hidrogênio

Abstract

Photobiomodulation (PBM) has been utilized and investigated in the field of sports medicine to expedite metabolic and structural responses in skeletal muscle, yielding effects such as increased intravascular microcirculation, decreased lactic acid production, enhancement of mitochondrial and contractile function, improvement in muscle antioxidant capacity, prevention of exercise induced cellular damage, and post-exercise strength recovery. Studies suggest that mitochondrial chromophores are directly involved in the primary and secondary mechanisms and effects of photobiomodulation, such as modulation of mitochondrial membrane potential (Delta Psi m) and stimulation of ATP biosynthesis. Currently, PBM has been associated with Static Magnetic Field (SMF) in clinical settings, potentiating the effects generated by photobiomodulation when used in isolation. However, the biochemical and molecular effects of PBM-SMF on myoblasts remain unknown. This study aimed to investigate the effects of photobiomodulation associated with static magnetic field (PBM-SMF) at different doses on C2C12 muscle cells in the presence or absence of hydrogen peroxide (H2O2), employed as a positive control. The acute effects of irradiation on cell viability, double-stranded DNA (dsDNA) release, nitric oxide (NO) and Reactive Oxygen Species (ROS) release, Delta Psi m, Complex IV activity of the Electron Transport Chain, and cell death (Apoptosis and Necrosis) were evaluated through spectrophotometric assays, fluorimetric and flow cytometry. The effects of PBM-SMF were tested before (pre-), after (post-), or simultaneously (co-exposure) with H2O2. Results demonstrated that the optimal efficacy of irradiation against peroxide in terms of cell viability, NO levels, dsDNA, and ROS was observed in co-treatment. Therefore, this condition was chosen for mitochondrial modulation assays. It was observed that PBM-SMF positively modulated Delta Psi m and complex IV under normal conditions and restored to normal levels when compared to cells exposed to H2O2. Flow cytometry analysis also revealed that the dose of 3J maintained the number of viable cells comparable to control (>60%; p>0.05), while cells irradiated with 20 J and/or with H2O2 significantly increased the number of apoptotic cells (3.5 times and 2.6 times, respectively; p <0.05) compared to control cells. In co-treatment with the 3J dose and H2O2, there was a 25% recovery in the number of viable cells compared to H2O2 alone (p=0.01). Therefore, it can be inferred that PBM-SMF in a normal and oxidative environment, using 3J of energy, can positively modulate myoblastic cells. However, when exposed to higher doses, even in a non-oxidative environment, it may cause and/or potentiate oxidative stress through increased mitochondrial activity, demonstrating a dose-dependent response profile. [resumo fornecido pelo autor]