N-3 polyunsaturated fatty acids reduce allergic type mediator release by human mast cells in vitro via inhibition of reactive oxygen species

Introduction: The increased ratio of n-6/n-3 polyunsaturated fatty acids (PUFA) in Western diets may contribute to the rapid increase in prevalence of allergic diseases. Mast cells (MC) are the key effector cells in allergy. The effect of different PUFA on MC activation and mediator release together with the contribution of reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) signaling routes was studied. Methods: Human MC lines (LAD2, HMC-1) were incubated for 24 h with long chain n-6 (arachidonic acid, AA) or n-3 (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) PUFA. Effects of PUFA on degranulation, mediator secretion (PGD2, TNF-α, IL-4 and IL-13), and generation of ROS were measured. Results: Incubation with PUFA did not reduce IgE-mediated degranulation by LAD2 cells. However, mediator release of ionomycin/ PMAstimulatedHMC-1 cellswas differentially regulated. AA incubation increased PGD2 and TNF-α (p