A diet rich in docosahexaenoic acid enhances reactive astrogliosis and ramified microglia morphology in apolipoprotein E epsilon 4-targeted replacement mice.

Docosahexaenoic acid (DHA) consumption reduces spatial memory impairment in mice carrying the human apolipoprotein E ε4 () allele. The current study evaluated whether astrocyte and microglia morphology contribute to the mechanism of this result. and mice were fed either a DHA-enriched diet or a control diet from 4 to 12 months of age. Coronal brain sections were immunostained for GFAP, Iba1, and NeuN. Astrocytes from mice exhibited signs of reactive astrogliosis compared to mice. Consumption of DHA exacerbated reactive astrocyte morphology in carriers. Microglia from -control mice exhibited characteristics of amoeboid morphology and other characteristics of ramified morphology (more processes, greater process complexity, and greater distance between neighboring microglia). DHA enhanced ramified microglia morphology in mice. In addition, mice fed the DHA diet had lower hippocampal concentrations of interleukin-7, lipopolysaccharide-induced CXC chemokine and monocyte chemoattractant protein 1, and higher concentration of interferon-gamma compared to -control mice. Our results indicate that a diet rich in DHA enhances reactive astrogliosis and ramified microglia morphology in mice.