In vitro modulatory effect of omega-3 polyunsaturated fatty acid (EPA and DHA) on phagocytosis and ROS production of goat neutrophils

An in vitro study was carried out to examine the influence of two fish-oil-derived long chain ω-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on goat polymorphonuclear leukocytes (PMN). Twelve Saanen healthy goats were used as blood donors. Neutrophils were isolated from blood and incubated with increasing concentration of EPA and DHA (25, 50, 100, 200 μM). Control samples were incubated in the absence of ω-3 PUFAs. Phagocytosis was evaluated by fluorescein-labeled Escherichia coli incorporation, while extracellular Reactive Oxygen Species (ROS) production was determined by cytochrome c reduction assay, which was selected among the others due to its specificity for extracellular superoxide anion release. Phagocytic activity was significantly increased by EPA (P < 0.05) and DHA (P < 0.01). Treating PMN with EPA does not affect extracellular ROS production which is, on the contrary, down-regulated by DHA. This effect was increased in experimental conditions which mimic pro-inflammatory challenges (stimulation with PMA). This study demonstrates that EPA and DHA may have beneficial effect on neutrophil function by increasing their phagocytosis activity and, in the meanwhile, decreasing the tissue damages due to extracellular release of ROS.