The effect of dietary n-3 fatty acids on in vivo platelet aggregation in the cerebral microcirculation.
Diets enriched in n-3 fish oil have been suggested to decrease coronary artery disease in part through their ability to decrease cyclooxygenase-dependent platelet aggregation. However little is known concerning the effect of n-3 fatty acids on in vivo platelet aggregation. The purpose of these experiments was to determine whether dietary n-3 fatty acids affect the rate at which platelet aggregation occurs in cerebral arterioles. Fish oil (200 mg eicosapentaenoic acid + 143 mg docosahexaenoic acid/kg), corn oil or water was given daily by gavage to mice (n = 30) for six weeks and then in vivo platelet aggregation was induced by the light plus dye method, which injuries the endothelium. Two additional groups of mice were acutely treated with saline or indomethacin (0.5 mg/kg, ip), with the latter serving as a positive control for therapeutic inhibition of platelet aggregation. Serum thromboxane B2 was analyzed by RIA. All fed groups gained weight equally. Serum thromboxane B2 was decreased by 40% in the fish oil group (p = 0.05 vs. corn oil, p = 0.07 vs. water). The mean (+/- SE) time to first aggregate in pial arterioles was 101 +/- 6, 91 +/- 6 and 101 +/- 9 seconds in the fish corn oil and water groups, respectively. Indomethacin significantly increased the time to first arteriolar aggregate by 35% (p < 0.002) and caused an 80% reduction in serum thromboxane. These studies show dietary fish oil produces a moderate reduction in serum TxB2 level and does not affect arteriolar platelet aggregation whereas indomethacin produces a drastic TxB2 reduction and significantly slows platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)
Heizer
M L
ML
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
McKinney
J S
JS
Ellis
E F
EF
D000818:Animals; D001921:Brain / Q000098:blood supply*; D004041:Dietary Fats / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D007213:Indomethacin / Q000494:pharmacology; D051379:Mice; D008833:Microcirculation / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects*; D013928:Thromboxane A2 / Q000378:metabolism
D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D013928:Thromboxane A2; D007213:Indomethacin