Effects of Geraniin on Platelet Aggregation and Interactions between Platelets and Neutrophils / 昆明医科大学学报

ABSTRACT

Objective To investigate the effects of geraniin on platelet aggregation and platelet-neutrophil interactions.Methods Platelet aggregation,in vitro and ex vivo,was determined by use of Born's method,and the binding of thrombin-stimulated platelets to neutrophils was observed based on the rosette assay.Intracellular calcium concentration of platelets was measured by using Fura-2-AM.Results Geraniin in vitro significantly inhibited arachidonic acid (AA)-,adenosine diphosphate (ADP)-,or platelet activating factor (PAF)-induced platelet aggregation,in a concentration-dependent manner.The medium inhibitory concentrations (IC50) were 2.4,0.4 and 1.1 μmol/L,respectively.Intragastric geraniin at 5 mg/kg markedly suppressed platelet aggregation induced by AA,ADP,or PAF.Geraniin decreased the total rise of [Ca2+]i,Ca2+ release,and Ca2+ influx,in a concentration-dependant manner.The IC50 values were 71.9,84.9,and 62.9 μmol/L,respectively.Geraniin decreased the binding of thrombin-stimulated platelets to neutrophils,and significantly inhibited washed platelet aggregation stimulated by fMLP-activated neutrophils.The IC50 values were 3.2 and 10.2 μmol/L,respectively.Conclusion It is suggested that geraniin inhibited platelet aggregation in vitro and ex vivo,decreased the calcium mobilization of platelets,and suppressed the interactions between platelets and neutrophils.