DHA-Enriched Phospholipids Exhibit Anti-Depressant Effects by Immune and Neuroendocrine Regulation in Mice: A Study on Dose- and Structure-Activity Relationship.

Abstract

It has been reported that eicosapentaenoic acid (EPA), especially EPA-enriched phospholipids (EPA-PL), significantly ameliorates depression-like behavior in mice, while the corresponding effect of docosahexaenoic acid (DHA) is weak. However, it is still unclear whether the limited effect of DHA on alleviating depression is remedied by dose and chemical structure adjustment to DHA-PL. A mouse model with depression is established by chronic unpredictable mild stress (CUMS) coupled with lipopolysaccharide (LPS) challenge to simulate the infection-triggered immune perturbation during chronic stress, and the effects of dietary 0.2% EPA-PL, 0.2% DHA-PL, 0.6% DHA-PL, and 0.6% DHA-enriched ethyl ester (DHA-EE) are comparatively investigated. The results demonstrate that dietary 0.6% DHA-PL, instead of 0.2% DHA-PL and 0.6% DHA-EE, significantly rescues the depression-like behavior with similar effects to 0.2% EPA-PL. Further studies reveal that dietary DHA-PL regulates immune dysregulation, inhibits neuroinflammation by NLRP3 inflammasome, and further improves monoamine systems and the hypothalamic-pituitary-adrenal (HPA) axis. The limited effect of DHA on depression is remedied by chemical structure adjustment to DHA-PL and three-fold dose. The present findings provide a potential novel candidate or targeted dietary patterns to prevent and treat depression.