Effects of dietary-induced alterations in rat brain docosahexaenoic acid accrual on phospholipid metabolism and mitochondrial bioenergetics: An in vivo 31P MRS study

Abstract

Evidence from 31P magnetic resonance spectroscopy (31P MRS) studies suggest that different psychiatric disorders, which typically emerge during adolescence and young adulthood, are associated with abnormalities in mitochondrial bioenergetics and membrane phospholipid metabolism. These disorders are also associated with deficits in omega-3 polyunsaturated fatty acids (n-3 PUFA), including docosahexaenoic acid (DHA) which accumulates in mitochondrial and synaptic membranes. The present study investigated the effects of dietary-induced alterations in brain DHA accrual during adolescence on phospholipid metabolism and bioenergetics in the adult rat brain using 31P MRS. During the peri-adolescent period (P21–P90), male rats were fed a diet with no n-3 fatty acids (Deficient, DEF, n=20), a diet fortified with preformed DHA (fish oil, FO, n=20), or a control diet fortified with alpha-linolenic acid (18:3n-3, n=20). On P90, 31P MRS was performed under isoflurane anesthetic using a 7T Bruker Biospec system. Compared with controls, brain DHA levels were significantly lower in adult rats fed the DEF diet (−17%, p≤0.0001) and significantly higher in rats fed the FO diet (+14%, p≤0.0001). There were no significant group differences for indices of bioenergetics, including adenosine triphosphate and phosphocreatine levels, or indices of membrane phospholipid metabolism including phosphomonoesters and phosphodiesters. Therefore, the present 31P MRS data suggest that rat brain DHA levels are not a significant predictor of mitochondrial bioenergetics or membrane phospholipid metabolism.

Encapsulation of Docosahexaenoic Acid Oil Substantially Improves the Oxylipin Profile of Rat Tissues

“…In these conditions, the DHA supplementation did not improve significantly DHA accretion in brain, as the DHA concentration was already high in the tissue, reaching more than 20% of total FA regardless of the diet. Our result contrasts with other studies where DHA proportion in brain was significantly increased by around 20% when rats fed a DHA enriched-diet as compared with the control ( 19 , 44 – 46 ). First, it has to be mentioned that important differences between studies were also highlighted by other authors concerning mouse models, where comparisons were difficult considering strains, brain regions, ages, and diet conditions ( 47 ).…”

Mass spectrometry imaging of mice brain lipid profile changes over time under high fat diet

“…Other studies have shown correlations between circulating levels of LPCs, SM, nonesterified fatty acids (NEFAs), PCs and obesity 17 , suggesting that alterations in lipid metabolism play an important role in the disease.…”