The mechanisms of acceleration of the platelet aggregation in the hypercholesterolemic rabbits were investigated. Rabbits were fed with 1% cholesterol-containing standard diet for 3 months.
No apparent increase was found in ADP-induced aggregation, but the marked acceleration of arachidonic acid (AA)-induced aggregation in the PRP (platelet rich plasma) and the slight acceleration in the WPS (washed platelet suspension) were found at end of 3 months' diet.
Analysis of the fatty acid composition of total lipids in the plasma revealed an increase of AA and a decrease of docosahexaenoic acid (DHA). Also the analysis of the fatty acid composition of phospholipids in the platelet revealed the increase of AA. The incorporation of 14C-AA into thromboxan B2 (TXB2) in platelet was increased approximately 2 times of that of the control. It was suggested that the acceleration of platelet aggregation in the hypercholesterolemic rabbits are caused by 1) the increase of AA component in plasma, 2) increased incorporation of AA into platelet and 3) the increase of AA metabolism to TXB2 within the platelets.
