Laser therapy modulates systemic inflammatory processes and muscle atrophy in an experimental model of sepsis in rats

Abstract Objective: The aim of this study was to determine the effectiveness of low-level laser therapy (LLLT) on the modulation of the systemic inflammatory processes and skeletal muscle morphology in an experimental sepsis model (cecal ligation and puncture, CLP). Study design: Seventy-two male Wistar rats were randomly divided into three groups: control group (CG); sepsis group (SG) where rats were submitted to CLP but without LLLT treatment, and the sepsis laser-treated group (SLG). Laser irradiation (GaAlAs laser, continuous wave, 808 nm, 30 mW, 48 s, 30 J/cm2, 0.028 cm2, 1.07 mW/cm2) was performed immediately after surgery and every 24 h at 4 points (on the middle of tibialis anterior and diaphragm, bilaterally), through the punctual contact technique. All sepsis animals were sacrificed at 6, 24, 48 and 72 h post-surgery. The immunohistochemistry analysis was used to verify the expression of proteins related to the regulation of muscle wasting (MuRF-1 and atrogin). In order to investigate the action of LLLT on inflammatory mediators in the rat sepsis model, two inflammatory cytokines IL-6 and IL-10, were evaluated. Results: The results showed that the laser-treated animals presented a lower IL-6 activity and decreased atrogin and MuRF-1 immunoexpression. However, no difference was observed in muscle cross-sectional area between the experimental groups. Conclusion: These results suggest that LLLT was able to decrease the systemic inflammation and muscle atrophy markers, preventing muscle protein degradation.