Background/Aims: A high-fat diet (HFD) is known to cause inflammation in the hypothalamus of rodents. Microglia, the resident immune-reactive cells and astrocytes are involved in this process. However, it is unclear whether these cells initiate the response, or are activated as a result of inflammation in neurons. Our aim was to investigate the effects of different fatty acids on a marker of inflammation (IL-6) in hypothalamic neurons.
Methods: We treated hypothalamic neurons mHypoE-N42 (N42) with different fatty acids and mixtures of fatty acids at physiological concentrations (200 µM) and measured IL-6 gene expression using semi-quantitative Real-Time PCR. Differences between groups were tested using Student’s t-tests.
Results: Palmitic acid (16:0) and decanoic acid (10:0) upregulated IL-6 (P<0.001) whiledocosahexaenoic acid (DHA) (22:6 n-3) and oleic acid (18:1 n-9) downregulated IL-6 (P<0.001). Eicosapentaenoic acid(EPA) (20:5 n-3), lauric acid (12:0) and octanoic acid (8:0) had no effect on IL-6 expression. When administered in combination with palmitic acid, both EPA and lauric acid were able to reduce PA induced inflammation (P<0.01 and P<0.001 respectively).
Conclusions: This study shows that fatty acids varying in chain length and degree of saturation elicit different outcomes in expression of the inflammatory marker IL-6 in neurons and confirm the well-documented anti-inflammatory effect of oleic acid and the polyunsaturated fatty acids, DHA and EPA, revealing differential effects, with DHA inhibiting inflammation and EPA reverting pre-existing inflammation.
Funding source(s): Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS) and a Scottish Universities Life Sciences Alliance (SULSA MSD) studentship