Effect of dietary alpha-linolenate/linoleate balance on collagen-induced platelet aggregation and serotonin release in rats.

Abstract

Male Sprague-Dawley rats at 3 weeks of age were weaned to a diet supplemented either with perilla seed oil [alpha-linolenic acid (alpha-LnA)/linoleic acid (LA) = 3.66] or with safflower seed oil (alpha-LnA/LA less than 0.01) for 5-6 weeks. The eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio in platelet phospholipids was much higher in the perilla oil group than in the safflower oil group. Platelet aggregability determined turbidometrically varied greatly among individual animals, and the difference in platelet aggregability between the two dietary groups was relatively small when higher concentrations (15 and 20 micrograms/ml) of collagen were used. However, when platelet aggregability was determined as an all-or-none phenomenon at lower concentrations (7.5 and 10 micrograms/ml) of collagen, a very distinct difference was observed between the two dietary groups; aggregability was much lower in the perilla oil group than in the safflower oil group. Collagen-induced serotonin release from platelets was significantly reduced in the perilla oil group as compared with the safflower oil group. These results emphasize the importance of estimating aggregability at threshold concentrations of collagen and confirm that dietary manipulation of the essential fatty acid balance could be useful in reducing the thrombotic tendency.