RESUMO
This study examined effects of dietary n-3 fatty acids on age-related changes in erythrocyte anion transport and susceptibility to oxidation. Blood was drawn from healthy adult volunteers before and after six weeks' supplementation (nine/group) with 4.0 g/day of safflower oil (containing 2.9 g n-6 fatty acids) or fish oil (containing 1.2 g long-chain n-3 fatty acids). Following density separation of young and old erythrocytes, membrane anion transport and cell membrane lipid composition were measured. Oxidative damage was measured in erythrocyte ghosts exposed to a free radical generator. Fish oil significantly increased 16:0 and 20:5n-3 in ghosts of both young and old cells, and 22:5n-3 and 22:6n-3 in old cells alone. Safflower oil increased 16:0, 18:0, 18:1n-9, and 22:5n-6 in ghosts of young cells only. The age-dependent increase in membrane anion transport (P < 0.01) was decreased by dietary fish oil supplementation, but not by safflower oil supplementation. Safflower oil and fish oil increased the susceptibility of both young and old erythrocytes to oxidative damage by free radical generation (P < 0.001).
Assuntos
Envelhecimento/sangue , Membrana Celular/metabolismo , Gorduras na Dieta/farmacologia , Eritrócitos/metabolismo , Ácidos Graxos/farmacologia , Adulto , Ânions , Transporte Biológico , Separação Celular , Envelhecimento Eritrocítico , Ácidos Graxos/administração & dosagem , Ácidos Graxos/sangue , Feminino , Óleos de Peixe/administração & dosagem , Radicais Livres , Humanos , Masculino , Lipídeos de Membrana/sangue , Oxirredução , Fosfolipídeos/sangue , Óleo de Cártamo/administração & dosagem , Sulfatos/sangue , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
The effects of cell age on erythrocyte phospholipid fatty-acid composition and deformability were examined in 20 healthy adults (11 male, 9 female) prior to and following 12 weeks of dietary supplementation with 3.5 g/day of safflower oil (high in n - 6 fatty acids) or fish oil (high in n - 3 fatty acids). In the absence of dietary supplementation, old erythrocytes demonstrated an increase in filtration time (P < 0.001), an increase in membrane phospholipid total n - 6 fatty acids (P < 0.01), and a decrease in total n - 3/total n - 6 ratio (P < 0.01) compared to young erythrocytes. Both safflower and fish oil supplementation attenuated age-related differences in membrane phospholipid total n - 6 and total n - 3 fatty acids. Fish oil supplementation also increased the proportion of n - 3 fatty acids (P < 0.01) and the n - 3/n - 6 ratio (P < 0.05) in the phospholipids of both young and old erythrocytes, and eliminated age-related differences in erythrocyte filtration time by reducing the relative filtration time of the old erythrocytes.