Li Haixin, Huang Ying, Wu Xian, Wu Ting, Cao Ying, Wang Qimei, Qiu Yuchang, Fu Weiming, Zhang Qun, Pang Jianxin
Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, People's Republic of China.
Department of Pharmacy, Shenzhen Hospital, Southern Medical University, Shenzhen, People's Republic of China.
Drug Des Devel Ther. 2018 May 23;12:1385-1398. doi: 10.2147/DDDT.S159210. eCollection 2018.
Hemocoagulase agkistrodon (HCA), a thrombin-like enzyme (TLE) from the venom of the Chinese moccasin snake (), has been used in clinical practice as a hemostatic compound. The aim of this study was to further investigate the pharmacological properties of HCA.
Sodium dodecyl sulfate or native polyacrylamide gel electrophoresis (SDS- or N-PAGE) as well as enzyme linked immunosorbent assays (ELISAs) were conducted to study the effects of HCA on the human plasma fibrinogen and prothrombin levels, as well as its in vitro interactions with some coagulation factors. In addition, the bleeding time effects of HCA in the mouse tail-bleeding model as well as its effects on the fibrinogen levels in rabbits were determined in vivo.
In vitro results revealed that HCA exerts its procoagulant activities by hydrolyzing fibrinogen into segments that are easier to be absorbed, reducing the risk of thrombus formation. Besides, HCA could significantly inhibit the activation of prothrombin at the concentration of 0.3 μM. Unexpectedly, we also found that HCA was able to strongly bind to factor X/Xa (in a ratio of 1:1) and thus inhibit the acceleration of active factor X to tissue plasminogen activator-catalyzed plasminogen activation, demonstrating that it could be less likely to lead to thrombus formation. Finally, in vivo results indicated that HCA could significantly shorten the bleeding time in the mouse tail-bleeding model and had no effect on the fibrinogen levels in rabbits.
In summary, HCA, a unique and new family member of TLEs, may become a new clinical drug for the prevention and treatment of hemorrhage due to its unique and complex interactions with the blood system. Clarification of these features will enable us to further understand the mechanism of action of HCA and then promote its further application in clinical practice as a therapeutic drug.
血凝酶蝮蛇（HCA）是一种从中国蝮蛇毒液中提取的类凝血酶（TLE），已作为一种止血化合物应用于临床实践。本研究的目的是进一步探究HCA的药理学特性。
采用十二烷基硫酸钠或天然聚丙烯酰胺凝胶电泳（SDS-或N-PAGE）以及酶联免疫吸附测定（ELISA）来研究HCA对人血浆纤维蛋白原和凝血酶原水平的影响，以及其在体外与一些凝血因子的相互作用。此外，在小鼠断尾出血模型中测定HCA对出血时间的影响，并在体内测定其对兔纤维蛋白原水平的影响。
体外实验结果显示，HCA通过将纤维蛋白原水解成更易被吸收的片段来发挥其促凝血活性，降低血栓形成风险。此外，HCA在浓度为0.3μM时能显著抑制凝血酶原的激活。出乎意料的是，我们还发现HCA能够与因子X/Xa（比例为1:1）强烈结合，从而抑制活性因子X对组织纤溶酶原激活剂催化的纤溶酶原激活的加速作用，表明其导致血栓形成的可能性较小。最后，体内实验结果表明，HCA能显著缩短小鼠断尾出血模型的出血时间，且对兔纤维蛋白原水平无影响。
综上所述，HCA作为TLEs的一个独特新成员，因其与血液系统独特而复杂的相互作用，可能成为预防和治疗出血的新型临床药物。阐明这些特性将使我们能够进一步了解HCA的作用机制，进而促进其作为治疗药物在临床实践中的进一步应用。
