The thrombolytic action of a proteolytic fraction (P1G10) from Carica candamarcensis

Abstract

A group of cysteine-proteolytic enzymes from C. candamarcensis latex, designated as P1G10 displays pharmacological properties in animal models following various types of lesions. This enzyme fraction expresses in vitro fibrinolytic effect without need for plasminogen activation. Based on this evidence, we assessed by intravital microscopy the effect of P1G10 on recanalization of microvessels after thrombus induction in the ear of hairless mice. Video playback of intravital microscopic images allowed measurement of blood flow velocity (mm/s) during the experimental procedure. Groups treated with 5 or 7.5mg/Kg P1G10 showed thrombolysis between 7-15min, without vessel obstruction. Ex vivo experiments demonstrated that platelet activation by ADP is impaired in a dose dependent manner following treatment with P1G10. The P1G10 action on plasma coagulation also showed that prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (aPTT, μg/uL) are increased in a dose dependent manner. In addition, P1G10 displayed fibrinogenolytic and fibrinolytic activities, both in a dose dependent manner. Each of these effects was suppressed by inhibition of the proteolytic activity of the fraction. The antithrombotic action of P1G10 can be explained by proteolytic cleavage of fibrinogen and fibrin, both key factors during formation of a stable thrombus. These results combined with prior evidence suggest that P1G10 has potential as thrombolytic agent.