高相对分子质量鼠尾藻多酚的抗凝血活性及对血小板内钙水平的影响

Effects of high molecular weight phlorotannins from Sargassum thunbergii Kuntze on anticoagulation activity and platelet cytosolic calcium level

目的:研究高相对分子质量鼠尾藻多酚(STI-3,Mr>1.0×105)的抗凝血活性及其对血小板内钙水平的影响。方法:Wistar大鼠灌胃给药测定STI-3对活化部分凝血活酶时间(APTT)、凝血酶原时间(PT)和凝血酶时间(TT)的影响;以新西兰白兔为实验动物制备洗涤血小板并应用流式细胞方法测定血小板内钙离子浓度。结果:STI-3(20mg/kg)在体内显著延长APTT(P<0.05)、PT(P<0.01)和TT(P<0.01),与相同剂量阿司匹林效果相近;与正常对照组相比,在二磷酸腺苷(ADP)刺激后1.0mg/mL和2.0mg/mLSTI-3两个剂量组血小板内钙离子浓度增加量(ΔC)均呈现显著性降低(P<0.05),且其抑制效果与1.0mg/mL阿司匹林相近。结论:STI-3可同时干扰内源性、外源性凝血因子的活性,具有显著的抗凝血活性;可显著减少兔洗涤血小板内钙释放及外钙内流。提示STI-3的抗凝血活性机制可能与其降低血小板内钙离子浓度密切相关。

Aim： To explore effects on anticoagulation activity and platelet cytosolic calcium level of high molecular weight phlorotannins from Sargassum thunbergii Kuntze （ STI-3, Mr 〉 1. 0 × 10^5） . Methods： Activated partial thromboplastia time （APTT）, prothrombin time （PT） and thrombin time （TT） were determined with Wistar rats treated with intragastric administration of STI-3. Washed platelets were prepared from rabbits and activated by adenosine diphosphate（ADP） before platelet cytosolic calcium level was measured by flow cytometry. Results： At the dosage of 20 mg/kg, STI-3 significantly prolonged APTT （ P 〈 0.05）, PT（ P 〈 0.01） and TT（ P 〈0.01）, which were close to those of aspirin at the same dose. Compared with the control group, after being stimulated by ADP, platelet cytosolic calcium level increments （AC） in two dosage groups of STI-3 of 1.0 and 2.0 mg/mL decreased significantly （P 〈 0.05）, and there was no significant difference among these two groups and aspirin group. Conclusion： STI-3 could interfere with the activities of endogenous and exogenous coagulation factors simultaneously and thus has remarkable anticoagulation activity. Furthermore, STI-3 could decrease Ca^2＋ released from intracellular storage and Ca^2＋ influx to the washed platelets of rabbits. Therefore, the anticoagulation mechanism of STP-3 may be closely related to the reduction of platelet cytosolic calcium level.