Effect of photobiomodulation of inflammatory cells on myoblasts

Abstract

Inflammatory cells invade muscle tissue after the occurrence of injury and orchestrate the tissue repair process. Among these cells, macrophages play a major role. Low-level laser (LLLT) has been widely used in clinical practice to accelerate the repair of muscle tissue, but little is known regarding its effect on macrophages and the implications of this modulation with regard to muscle cells. The aim of the study proposed is to analyze the effects of LLLT on macrophage proliferation and the production of cytokines and enzymes by activated macrophages as well as the effect of products secreted by these cells on myoblasts. Macrophages of the lineage J774 will be used in this study, which will be activated to simulate an inflammatory situation and will receive two different laser irradiation parameters (780 nm, 70 mW, 3 J/cm2 and 660 nm, 15 mW, 7.5 J/cm2). The methodology will consist of macrophage viability and proliferation assays, analyses of the expression of cytokines and inflammatory enzymes (TNF-±, IL-6, IL-10, COX-2) involved in muscle repair and an evaluation of the effects of supernatants from macrophage cultures on the viability, proliferation and differentiation (by immunofluorescence staining) of cultured C2C12 myoblasts. In each experimental situation, non-irradiated cells will serve as controls. Three independent experiments will be performed under each condition and the results will be statistically analyzed. (AU)