RESUMO
Objective: The objective of this study is to evaluate the potential effects of photobiomodulation (PBM) on cell proliferation and extracellular matrix production of human fibroblasts (FN1) cultured in 2D. Background: Patients with healing difficulties suffer injuries that take time to recover. In addition, aging can be seen in our faces daily when we look in the mirror; in both situations, collagen production is reduced. Fibroblasts act in the beginning and at the end of the inflammation phase, signaling to immune agents, and platelets, and producing collagen, coordinating repair. PBM increases cell viability, proliferation, and mRNA production. Methods: Human fibroblasts were irradiated three times after cell seed (after 24, 48, and 72 h) using a gallium-aluminum arsenideGaAlAs low-level laser (LLL). Cell viability, proliferative response, synthesis of collagen types I and III, and soluble collagen production were analyzed. The statistical significance of differences between groups was determined using unpaired one-way analysis of variance (ANOVA) p < 0.05. Results: PBM increased significantly the number of fibroblasts, and the production of collagen types I (Col I) and III (Col III), after three sessions of LLL with 2.5 J per session, every 24 h, for 3 consecutive days; total energy delivered after 72 h is 7.5 J. Conclusions: This energy density of LLL increases fibroblast proliferation and collagen production in vitro without side effects.