Increased n-3 polyunsaturated fatty acid content of red blood cells from fish oil-fed rabbits increases in vitro lipid peroxidation, but decreases hemolysis.
In view of a possible relationship between fish oil, lipid peroxidation, and atherosclerosis, the in vitro lipid peroxidation susceptibility of red blood cells (RBCs) from rabbits on conventional (-FO) and fish oil-enriched diets (+FO) was investigated. The diet caused substantial increases in the RBC concentrations of n-3 polyunsaturated fatty acids (PUFAs), in combination with decreases in the concentration of oleic acid (18:1) and linoleic acid (18:2). Cumene hydroperoxide-induced oxidative stress led to increased overall fatty acid peroxidation in +FO RBCs compared with with -FO RBCs, as quantitated by GLC fatty acid analysis. However, the increased overall susceptibility to lipid peroxidation of +FO RBCs was not reflected in increased peroxidation of every individual fatty acid. This was observed for endogenous arachidonic acid (20:4) as well as, in separate experiments, for exogenously added parinaric acid (PnA). The increased cumene hydroperoxide-induced PUFA oxidation in +FO RBCs was accompanied by a lesser extent of hemolysis. To account for these observations, it is proposed that the increased n-3 PUFA content of +FO RBCs serves as an oxidizable buffer. The present data suggest that oxidation of fatty acids can occur until a critically low level of intact phospholipid in the RBC membrane is reached, after which the membrane destabilizes and hemolysis occurs. At the same time, the PUFA buffer in +FO RBCs could also prevent oxidative damage to specific membrane proteins, which could also help prevent cell lysis.
van den Berg
J J
JJ
Children's Hospital Oakland Research Institute, CA 94609.
de Fouw
N J
NJ
Kuypers
F A
FA
Roelofsen
B
B
Houtsmuller
U M
UM
Op den Kamp
J A
JA
D000818:Animals; D016718:Arachidonic Acid / Q000097:blood; D004041:Dietary Fats / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000097:blood; D005260:Female; D005395:Fish Oils / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects*; D011817:Rabbits
D004041:Dietary Fats; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D015525:Fatty Acids, Omega-3; D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D016718:Arachidonic Acid; C013641:parinaric acid