ABSTRACT
Objective:To evaluate the effect how Subtilisin FS33 affect thrombotic and fibrinolytic systems in vitro and in vivo. Method:Activity of Subtilisin FS33 was measured by clot liquefaction time(CLT) . On the model of 10% FeCl3 induced thrombi of carotid arteries in rats,various doses of Subtilisin FS33 were injected to the rats,and the fibrinolytic effect was observed. Results:0.5 g of the unheated blood clots gradually dissolved within 45 min,whereas the blood clots heated at 80℃ for 30 min dissolved within 3 h. This indicated that the enzyme was able to degrade blood clots in the absence of endogenous fibrinolytic factors. The experiment in vivo indicated that high dose subtilisn group could significantly prolong CT(coagulation time ) ,PT(prothrombin time) ,TT(thrombin time ) ,APTT(activated partial thromboplastin time) ,reduce ELT(euglobulin lysis time) ,decrease the content of FIB(fibrinogen) ,increase the content of FDP(fibrinogen degradation products) . D-dimer of all experimental groups waspositive. The venous thrombus in lung and kidney was dissolved totally or partly as observed by pathological section. Conclusion:Both thrombolytic effects of Subtilisin FS33 in vitro and in vivo were significant and the mechanisms might be associated with enhancing anticoagulation activity and fibrinolysis.