木瓜蛋白酶体外对血小板聚集的抑制作用

目的：以洗涤血小板为模型,观察木瓜蛋白酶在体外对血小板聚集的抑制作用,以探讨其抗血栓作用的可能机制。方法：将不同剂量木瓜蛋白酶与洗涤血小板作用,以血小板聚集分析仪检测ADP、花生四烯酸（AA）、胶原和凝血酶诱导的血小板最大聚集率,以流式细胞仪检测活化血小板膜纤维蛋白原受体（FIB-R）和P-选择素表达水平,以SDS-PAGE分析血小板肌动蛋白聚合体的变化。检测ADP诱导的原发性高血压（PH）及急性心肌梗死（AMI）患者血小板最大聚集率和FIB-R表达水平。结果：木瓜蛋白酶剂量依赖性地抑制血小板聚集,降低血小板最大聚集水平,血小板聚集水平与木瓜蛋白酶剂量呈负相关（P〈0.01）。木瓜蛋白酶剂量依赖性地抑制ADP诱导的血小板FIB-R表达,降低FIB-R表达水平（P〈0.01）。木瓜蛋白酶降低ADP诱导的血小板膜P-选择素表达水平和抑制肌动蛋白聚合体增加（P〈0.01）。木瓜蛋白酶抑制PH及AMI患者血小板聚集和FIB-R表达（P〈0.01）。结论：木瓜蛋白酶通过抑制活化血小板膜纤维蛋白原受体的表达,并抑制肌动蛋白聚合以及释放反应从而剂量依赖性地抑制血小板的聚集反应,有抗血栓形成作用。

In vitro inhibitory effects of papain on platelet aggregation

AIM:To observe the in vitro inhibitory effects of papain on platelet aggregation by washed platelet model,and explore the possible antithrombotic mechanism of papain.METHODS:Human washed platelets were mixed with different doses of papain.The maximal ratio of platelet aggregation induced by 5adenosine liphosphate-disodium salt(ADP),arachidonic acid(AA),collagen and thrombin,respectively,was measured with platelet aggregation analyzer.The expressions of fibrinogen receptor(FIB-R) and pselectin(CD62p) on external membrane of activated platelet were determinated with flow cytometry.The changes of factin cytoskeletal structure in activated platelet were analyzed by SDS-PAGE.Platelet rich plasma(PRP) of patients with primary hypertension (PH) or acute myocardiac infarction(AMI) was treated to determinate the levels of aggregation and FIB-R expression.RESULTS:Papain significantly inhibited platelet aggregation in a dose-dependent manner and reduced the levels of platelet aggregation,there was remarkably negative correlation between platelet aggregation level and papain dose(P＜0.01).Papain notably inhibited FIB-R expression and decreased the levels of FIB-R expression activated by ADP in a dose-dependent manner.Papain reduced P-selectin expression on external membrane and lessened f-actins of platelet triggered by ADP.Papain significantly inhibited the levels of aggregation and FIB-R expression of platelets activated by ADP in patients with PH and AMI(P＜0.01).CONCLUSION:Papain can inhibit the expression of fibrinogen receptor on external membrane of activated platelet and polymerization or release reaction,so the thrombocytic aggregation are inhibited in a dose-dependent manner,and papain has the effect of anti-thrombogenesis.