Fibrin(ogen)olytic character of FIIa isolated from Agkistrodon acutus venom

Abstract

Aim: To investigate the fibrin(ogen)olytic character of FIIa isolated from Agkistrodon acutus venom in vitro and in vivo.

Methods: 125I-labeled human plasma clot lysis was measured in vitro and rabbit carotid artery thrombosis was as an in vivo model.

Results: In vitro, urokinase (UK) at 25, 35, 40, 45, 60 kU/L and FIIa at 0.08, 0.23, 0.4, 0.5, and 0.7 g/L resulted an equivalent clot lysis (20%, 40%, 50%, 60%, and 80%). UK at 25 to approximately 60 kU/L induced 27.3%+/-3.6%, 35.2%+/-2.3%, 39.3%+/-2.4%, 44.2%+/-4.6%, and 51.1%+/-1.2% fibrinogen degradation. But FIIa at 0.08 approximately -0.7 g/L induced 95.4%+/-0.3%, >95.6%, >95.6%, >95.6%, >95.6% fibrinogen degradation respectively. In vivo, UK 40 kU/kg and FIIa 1.0 mg/kg reduced the weight of residual thrombus to 9.0+/-2.5 mg and 7.8+/-3.5 mg compared with negative control group (30.0+/-5.4 mg). But the fibrinogen degradation rate after UK 40 kU/kg and FIIa 1.0 mg/kg treatment was 24.4%+/-6.2% and 4.1%+/-7.8%, respectively (P<0.05, n=6). The order of the lysis speed after UK 125 kU/L treatment was platelet poor plasma (PPP) clots>the whole blood clots>platelet rich plasma (PRP) clots. The sequence for FIIa 0.4 g/L was PRP >PPP >whole blood clots.

Conclusion: At the same percentage of clot lysis, FIIa degraded more fibrinogen than UK did in vitro but less fibrinogen than UK did in vivo. The order of the lysis speed was PPP>whole blood clots>PRP clots for UK and PRP>PPP>whole blood clots for FIIa.