Efeitos de ácidos graxos na ativação de macrófagos murinos

Abstract

Macrophages play an essential role in the body's homeostasis. They are present in all tissues and have numerous phenotypes that are adapted to the tissue environment. Several parameters and molecules are used to measure the activation of macrophages, such as morphology, activation of arginase, cytokines production and surface molecules expression. In this context, polyunsaturated fatty acids have been shown to be fundamental since they are used by macrophages as part of the membrane structure and have immune activity, influencing the physiology and activation of macrophages during stimulation or infection. Thus, the aim of this work was to evaluate the changes induced by in vitro supplementation with polyunsaturated fatty acids (PUFAs) in murine macrophages. To do this, peritoneal macrophages from C57BL/6 mice recruited with thioglycolate at 3% was used. After removal of the peritoneal lavage with PBS, the cells were counted and plated in complete medium. After the time for adhesion, cells not adhered were washed and then received PUFAs in concentrations of 100μM (EPA and DHA, the omega-3 family, AA, omega-6 family and purified CLA). After 48 hours of lipid culture, or subsequent stimulation with IFN-γ + LPS or IL-4 or infection with Trypanosoma cruzi, analyzes were performed. We observed that EPA increased adherence, phagocytic capacity, frequency of MHCIIhi, CD124+ and CD206+ positive cells. Our results also showed that EPA, DHA and AA reduced NO production in cells stimulated with IFN-γ + LPS and also increased expression of TLR2. In addition, AA increased arginase activity, whereas CLA increased mRNA for iNOS. In the context of infection, EPA, DHA and AA were able to reduce the number of parasites per cell, but only EPA reduced the percentage of infected cells. In conclusion the lipids were able to modulate macrophage activation, and EPA was the lipid which had more impact in the activation of peritoneal macrophages by increasing the expression and frequency of cells positives to activation molecules, impaired the production of NO and IL-6 in macrophages that were stimulated and enhanced the number of cells capable of eliminate the T. cruzi amastigots.