Effect of different concentrations of omega-3 fatty acids on stimulated THP-1 macrophages

BACKGROUND: Inflammation plays a central role in chronic diseases occurring in the contemporary society. The health benefits of omega-3 (n-3) fatty acids (FAs), mostly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been reported. However, their mechanisms of action are poorly understood. We explored dose and time effects of EPA, DHA, and a mixture of EPA + DHA on the expression of inflammatory genes in stimulated macrophages. METHODS: Lipopolysaccharide was used to stimulate human THP-1 macrophages. Cells were incubated in different conditions in the presence of n-3 FAs and LPS, and mRNA levels of inflammatory genes were measured by real-time PCR. Cytokine levels in culture media were measured. RESULTS: The mixture of EPA + DHA had a more effective inhibitory effect than either DHA or EPA alone, DHA being more potent than EPA. For both EPA and DHA, 75 μM of FAs had a more important anti-inflammatory effect than 10 or 50 μM. For gene expression, EPA had the greater action during the post-incubation (after LPS treatment) condition while DHA and EPA + DHA were more potent during the co-incubation (n-3 FAs and LPS). Cytokine concentrations decreased more markedly in the co-incubation condition. CONCLUSIONS: These results suggest that in stimulated macrophages, expression levels of genes involved in inflammation are influenced by the dose, the type of n-3 FAs, and the time of incubation.