Low level laser therapy on injured rat muscle

Although several studies show the clinical effectiveness of low level laser therapy (LLLT) in facilitating the muscle healing process, scientific evidence is still required to prove the effectiveness of LLLT and to clarify the cellular and molecular mechanisms triggered by irradiation of injured tissue with laser radiation. Here we evaluate the effect of different LLLT doses, using continuous illumination (830 nm), in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, through the quantification of cytokines and histological analysis of muscle tissue. We verified all applied doses produce an effect on reducing the number of inflammatory cells and the concentration of pro-inflammatory TNF-α and IL-1β cytokines. The best results were obtained for a radiant power of 40 mW. The results may suggest a biphasic dose response curve.