Threshold changes in rat brain docosahexaenoic acid incorporation and concentration following graded reductions in dietary alpha-linolenic acid

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• 作者：Ameer Y. Taha^a ; ^{ataha@ucdavis.edu" class="auth_mail" title="E-mail the corresponding author} ; Lisa Chang^b ; Mei Chen^b
• 关键词：α-LNA ; alpha-linolenic acid ; ANOVA ; analysis of variance ; AA ; arachidonic acid ; cPLA2 ; Ca2+-dependent cytosolic phospholipase A2 ; iPLA2 ; Ca2+-independent phospholipase A2 ; CE ; cholesteryl ester ; ChoGpl ; choline glycerophospholipid ; COX ; cyclooxygenase ; DHA ; docosahexaenoic acid ; EtnGpl ; ethanolamine glycerophospholipid ; FAMEs ; fatty acid methyl esters ; GC ; gas-chromatography ; LA ; linoleic acid ; LOX ; lipoxygenase ; PtdIns ; phosphatidylinositol ; PET ; positron emitting tomography ; PtdSer ; phosphatid
• 刊名：Prostaglandins, Leukotrienes and Essential Fatty Acids
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：105
• 期：Complete
• 页码：26-34
• 全文大小：961 K

文摘

This study tested the dietary level of alpha-linolenic acid (α-LNA, 18:3n-3) required to maintain brain ¹⁴C-Docosahexaenoic acid (DHA, 22:6n-3) metabolism and concentration following graded α-LNA reduction.

Methods

Fischer-344 (CDF) male rat pups (18–21 days old) were randomized to the AIN-93G diet containing as a % of total fatty acids, 4.6% (“n-3 adequate”), 3.6%, 2.7%, 0.9% or 0.2% (“n-3 deficient”) α-LNA for 15 weeks. Rats were intravenously infused with ¹⁴C-DHA to steady state for 5 min, serial blood samples collected to obtain plasma, and brains excised following microwave fixation. Labeled and unlabeled DHA concentrations were measured in plasma and brain to calculate the incorporation coefficient, k*, and incorporation rate, J_in.

Results

Compared to 4.6% α-LNA controls, k* was significantly increased in ethanolamine glycerophospholipids in the 0.2% α-LNA group. Circulating unesterified DHA and brain incorporation rates (J_in) were significantly reduced at 0.2% α-LNA. Brain total lipid and phospholipid DHA concentrations were reduced at or below 0.9% α-LNA.

Conclusion

Threshold changes for brain DHA metabolism and concentration were maintained at or below 0.9% dietary α-LNA, suggesting the presence of homeostatic mechanisms to maintain brain DHA metabolism when dietary α-LNA intake is low.