新的尖吻蝮蛇蛇毒类凝血酶Agacutin止血作用的实验研究

Experimental study on hemostatic effects of agacutin, a novel thrombin-like enzyme from Agkistrodon acutus

目的:研究类凝血酶Agacutin的止血效果.方法:新西兰白兔静脉注射Agacutin,观察血凝和纤溶指标;小鼠皮下注射Agacutin,采用小鼠剪尾试验测定其止血效果.结果:静脉注射Agacutin 0.01～0.05U·kg-1后,各组全血凝固时间与给药前相比均有不同程度的缩短(44.9%～60.5%),给药后30 min药效达高峰,药效持续24h.与给药前比较,各组兔血纤维蛋白原含量和血粘度在给药后有不同程度的降低,这与血液凝固时间缩短一致.试验结果显示,Agacutin对部分凝血活酶时间、血小板数量、血小板释放活性、血小板体外聚集、优球蛋白凝固时间均无明显影响,但对优球蛋白溶解时间有不同的缩短,显示有弱的溶栓活性.腹腔注射Agacutin0.5～2 U·kg-1剂量后,小鼠剪尾出血时间有不同程度的缩短(24%～66%).结论:Agacutin在血管内引起较高浓度的可溶性纤维蛋白且不激活凝血因子Ⅱ和XIII,在伤口部位加速止血,在正常的血管内,不会造成血栓形成.

AIM： To study the hemostatic effects of agacutin in vivo . METHODS： After agacutin was administrated, the indexes on blood coagulation and fibrinogenlysis system were assayed and the hemostatic effect was obtained by observing the mouse tail bleeding time. RESUITS： The intravenous injectiou of 0.01 -0.05 U· kg^-1 markedly shortened 44.9 % - 60.5 % of the rabbit blood coagulation time. After administration, the peak effect appeared in 30 min and the effect delayed for 24 h. The rabbit blood fibrinogen concentration and blood viscosity were decreased, which coincided with the effect of shortening of blood coagulation time. Agacutin had no influence on APTT ,the platelet count, platelet releasing activity, platelet in vitro aggregation, and euglobulin coagulation time （ECT）, but agacutin had a weak fibrinolyric activity. In vivo, the ip administration of 0.5 - 2.0 U· kg^- 1 shortened 24% - 66% of the mouse tail bleeding time. CONCLUSION： Agacutin causes a higher concentration of soluble fibrin level in vessel and it does not activate prothrombin （Ⅱ factor） and ⅩⅢ factor. The hemostatic function is promoted at the wound. In normal vessel, the soluble fibrin does not form insoluble fibrin clot which resulted in thrombosis in vivo.