Effects of acidic polysaccharide from holothuria leucospilota on platelet aggregation in rabbits

Platelet aggregations induced by acidic polysaccharide from Holothuria leucospilota (Brandt) (HL-P) 2.56-320μg/ ml in vitro and 2 mg/kg iv were observed in rabbits. The results showed that HL-P had no effect on the aggregation of platelet treated with anticoagulants, trisodium citrate or EDTA-Na2, and could mildly induce the aggregation of platelet treated with heparin. A significant proaggregatory effect on blood platelet suspended in modified Tyrode’ s solution was caused by HL-P, and potentiated by Ca2+ and Mg2+. HL-P prompted ADP-induced platelet aggregation to a certain extent. However, HL-P produced a very significant inhibition on thrombin-induced platelet aggregation. The amount of platelets was diminished by HL-P.