Abstract
Objectives
The purpose of the present study was to investigate the hypothesis that lifetime n-3 polyunsaturated fatty acids (PUFA) intake improved depression through serotonergic pathway in post-menopausal rats with chronic mild stress (CMS) and maternal separation (MS).
Methods
Female rats were fed diets with 0% or 1 energy % n-3 PUFA during lifetime from embryonic day (ED) 0 to postnatal day (PND) 112, or 1% n-3 PUFA before weaning (ED 0-PND 20), or after weaning (PND 20–112). The rats in four diet group were allocated to brief separation from dam (non-MS group) or long-term separation (MS group) on PND 2–14, and then underwent CMS on PND 91–105 after ovariectomy. Thus, there were eight groups in total (n = 8/group).
Results
MS + CMS increased depressive behaviors, and modified hypothalamic-pituitary-adrenal (HPA) axis activity, inflammation, serotonergic and glutamatergic neurotransmission, and related miRNAs as compared to CMS alone. N-3 PUFA decreased depressive behaviors by decreasing immobility while increasing swimming during forced swim test, and increasing sucrose preference in rats with MS + CMS and with CMS. N-3 PUFA decreased HPA axis activity by modifying expressions of corticotrophin releasing factor and glucocorticoid receptor, and levels of adrenocorticotropic hormone and corticosterone. N-3 PUFA also reduced levels of TNF-α, IL-1β, IL-6, PGE2, and miRNA-218, and increased serotonergic neurotransmission, including expressions of cAMP response element binding protein, brain-derived neurotrophic factor and serotonin 1A receptor, and serotonin level, and expression of miRNA-155. In addition, lifetime supplementation of n-3 PUFA had greater effect than pre- or post-supplementation. N-3 PUFA had no effect on glutamatergic pathway including α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor and N-methyl-D-aspartate receptor.
Conclusions
The present study suggested that lifetime n-3 PUFA improved depression in post-menopausal rats with MS + CMS through modulation of serotonergic pathway by decreasing HPA axis activity but not glutamatergic pathway.
Funding Sources
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2018R1A2B6002486).
N-3 Polyunsaturated Fatty Acid Improved Depression via Neuroendocrine and Serotonergic System in Post-Menopausal Rats with Maternal Separation and Chronic Mild Stress