Effects of moderate dietary supplementations with n-3 fatty acids on macrophage and lymphocyte phospholipids and macrophage eicosanoid synthesis in the rat.
The effects of a moderate dietary intake of n-3 polyunsaturated fatty acids were determined on the eicosanoid synthesis by rat peritoneal macrophages: the availability of arachidonic acid (20:4 (n-6)) and eicosapentaenoic acid (20:5 (n-3] in the membrane phospholipids of peritoneal macrophages and splenic lymphocytes and the synthesis of the main eicosanoids were evaluated in parallel. The n-6/n-3 ratio was decreased from 13.5 in the control diet rich in 18:2(n-6) to about 2 by an addition of either linseed oil providing 18:3(n-3) (linseed oil diet) or fish oil providing 20:5(n-3) and 22:6(n-3) (fish oil diet). The dietary linoleic acid content was at least 3.5% of energy in each diet. In peritoneal macrophage and splenic lymphocyte membrane phospholipids, arachidonic acid content was significantly decreased with the linseed oil and fish oil diets. 20:5(n-3) content was significantly raised up in the linseed oil group (3-fold in macrophage phospholipids) and more strikely in the fish oil group (7-fold). In response to a stimulation by the calcium ionophore A23187, peritoneal macrophages released 6-ketoPGF1 alpha, TXB2, PGE2 and LTB4 and/or 5, but no or few peptidoleukotrienes. The linseed oil did not affect significantly the synthesis of these eicosanoids, except for LTB5, which was increased 2-fold. In contrast, the fish oil diet led to significant decreases in the productions of 6-ketoPGF1 alpha and PGE2 (-50%) and LTB4 (-40%) and to a 10-fold increase in the release of LTB5. TXB2 was also decreased (-35%), but not significantly. These results and the parallel evolutions of the two ratios 20:4(n-6)/20:5(n-3) and LTB4/LTB5 showed that eicosanoid synthesis is greatly dependent on the relative availability of the two substrates in competition.
Brouard
C
C
Laboratoire Physiologie Métabolique et Nutrition, Université P. et M. Curie, Paris, France.
Pascaud
M
M
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D015232:Dinoprostone / Q000096:biosynthesis; D015777:Eicosanoids / Q000096:biosynthesis*; D015118:Eicosapentaenoic Acid / Q000378:metabolism; D005395:Fish Oils; D015289:Leukotrienes / Q000096:biosynthesis; D008043:Linseed Oil; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D010529:Peritoneal Cavity / Q000166:cytology; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000166:cytology; D013929:Thromboxane B2 / Q000096:biosynthesis
D001095:Arachidonic Acids; D004042:Dietary Fats, Unsaturated; D015777:Eicosanoids; D005395:Fish Oils; D015289:Leukotrienes; D008563:Membrane Lipids; D010743:Phospholipids; D016718:Arachidonic Acid; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D008043:Linseed Oil; D015118:Eicosapentaenoic Acid; D015232:Dinoprostone