Dietary fish oil n-3 polyunsaturated fatty acids and alpha-linolenic acid differently affect brain accretion of docosahexaenoic acid and expression of desaturases and sterol regulatory element-binding protein 1 in mice.
Whether preformed dietary docosahexaenoic acid (DHA) is required for brain accretion has not been clearly determined. In this study, we investigated in mice the different effects of dietary longer-chain n-3 polyunsaturated fatty acids (PUFAs) and α-linolenic acid (LNA) on brain accretion of DHA and the expression of associated desaturases and transcription factors. C57 BL/6J mice were fed for 3 months with four fish oil n-3 PUFA diets--lower, low, high and higher (0.46%, 0.91%, 1.73% and 4.29% total energy, respectively); a flaxseed oil n-3 PUFA (5.01% total energy) diet; and an n-3 PUFA-deficient diet, respectively. Either fish oil or flaxseed oil n-3 PUFA diets increased DHA concentrations in the brain. However, the flaxseed oil n-3 PUFA diet was less effective than the fish oil diet with higher amount of n-3 PUFA in increasing brain DHA content. Furthermore, the expressions of delta-6 desaturase (D6D) and sterol regulatory element binding protein 1 (SREBP-1) in the liver were down-regulated by all fish oil diets with different amounts of n-3 PUFAs, as well as by the flaxseed oil n-3 PUFA diet, whereas in the brain, D6D, delta-5 desaturase (D5D) and SREBP-1 expressions were down-regulated by the higher fish oil n-3 PUFA diet rather than by other fish oil n-3 PUFA and the flaxseed oil n-3 PUFA diets. These results suggest that preformed dietary DHA, different from those converted by LNA inside the body, is better for brain accretion. Dietary longer-chain n-3 PUFAs affect expressions of D6D, D5D and SREBP-1 in the brain differently from their precursor LNA.
Zhu
Haiyan
H
Clinical Nutrition Center, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
Fan
Chaonan
C
Xu
Feng
F
Tian
Chunyu
C
Zhang
Feng
F
Qi
Kemin
K
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D017931:DNA Primers; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology*; D005395:Fish Oils / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051780:Sterol Regulatory Element Binding Protein 1 / Q000378:metabolism*; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000494:pharmacology*
D017931:DNA Primers; D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; C497388:Srebf1 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D044943:Fatty Acid Desaturases