Anti-inflammatory effects of n-3 polyunsaturated fatty acids in THP-1 macrophages: promising in-vitro insights

Abstract

Uncontrolled inflammation is a one route to the pathogenesis and development of inflammatory diseases. The scientific literature has reported many evidences supporting the notion that polyunsaturated fatty acids (PUFAs) belonging to the family of n-3 including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have an anti-inflammatory function. Although much has been learned about EPA and DHA, so many questions remain unanswered, including the differential effects on health of DHA and EPA as well as the dose-response effect on clinical outcomes. The present study is aimed to investigate the effect of the PUFAs; EPA and DHA in the inflammatory responses in LPS-stimulated THP-1 macrophages. Cells were incubated for 24 and 48 hours with EPA and DHA. Cell viability test were used to determine the viability of cells during and after incubation. Doses concentrations of 0.09 and 0.45 mM for both EPA and DHA were utilized to study the expression levels of inflammatory cytokines that were measured by ELISA test. All data were presented as SEM and subjected to normality test by Anderson and Pearson tests and the statistical significance difference was determined via one-way ANOVA test. Our study revealed interesting findings that are in a significant agreement to other studies in the literature. DHA illustrated a decrease on the levels of IL-6 in LPS-stimulated THP-1 cells treated with 0.09 mM, and a greater reduction with 0.45 mM DHA concentration (P<0.001). Moreover, DHA in our study, achieved no statistically significant difference in TNF-alpha inflammatory cytokines compared to cells alone (P<0.001). On the other hand, LPS-stimulated THP-1 cells, when subjected to EPA, it showed a significant decline in both IL-6 and TNF-alpha in the higher dose only and failed to express a statistically significant difference in 0.09 mM (P<0.001). In conclusion, our data support the notion that PUFAs represented in EPA and DHA, are capable to reduce the expression of inflammatory cytokines. DHA stands out as a more potent anti-inflammatory agent which is a suggestive for a valuable marker to fight chronic diseases. Both in-vivo animals and human trials are urgently demanded to validate our current data.