The thrombopenic effect of ellagic acid in the rat. Another model of platelet stimulation "in vivo"

Abstract

In the rat, intravenous injection of large doses (30 mg/Kg) of ellagic acid (EA) induced a decrease in the plasma level of fibrinogen and in the blood platelet content and an increase of the activated partial thromboplastin time. The long-lasting thrombocytopenia was inhibited by heparin (4 mg/Kg), defibrase (20 U/Kg), clocoumarol (4 mg/Kg) and CCI 17810 (120 mg/Kg). It was not inhibited by aspirin (90 mg/Kg), indomethacin (8 mg/Kg), ketoprofen (4-10 mg/Kg), epsilon-aminocaproic acid (150 mg/Kg), methysergide (4 mg/Kg), chlorpromazine (10 mg/Kg) and promethazine (4 mg/Kg). On the contrary, the small doses of indomethacin (4 mg/Kg) and of ketoprofen (0.5-2 mg/Kg) increased the thrombopenic effect of EA. EA induced the accumulation of Cr51-labelled platelets into the lungs and the liver, accompanied by a 64% fall in Cr51 blood radioactivity. The platelet stimulating effect of EA would depend on an intravascular coagulation which occurs in the whole cardiovascular system. It is suggested that the pro-aggregating derivatives of arachidonic acid had a minor role in this stimulation. The intravascular coagulation induced by EA was accompanied by a swelling of the lymph nodes and of the spleen. In immune platelet depleted rats, EA induced only the swelling of lymph nodes.