Effects of Philodryas baroni snake venom on platelets and blood coagulation

MATIAS N. SANCHEZ; MARIA E. PEICHOTO; OFELIA ACOSTA; MARCELO L. SANTORO

Simposio; Platelets 2012: 7th International Platelet Symposium; 2012

Victims of P. baroni snakebites commonly manifest hemorrhagic lesions at the site of the bite. However, the composition and biological activities of the venom from this South-American "colubrid" snake have not been studied yet. Thus, herein, we studied its protein composition by 1D and 2D SDS-PAGE, as well as its effects on the hemostatic system. Proteins in the range of 50-80 kDa, which were more densely stained in one-dimensional gels, were also observed in the form of several acidic spots (pI 3.5-7.0) in two-dimensional gels. The venom displayed proteolytic activity towards azocollagen, with a specific activity of 75.5 U/mg, and rapidly hydrolyzed the Aa-chain of fibrinogen, leaving the γ-chain unaffected. 1,10-phenanthroline (5 mM, final concentration) completely abolished the proteolytic activity of the venom. However, 5 mM PMSF had only a partial inhibitory effect on this activity. Prominent hemorrhage developed in mouse skin after intradermal injection of the crude venom, and its minimum hemorrhagic dose was 13.9 µg. P. baroni venom showed no platelet pro-aggregating activity per se up to a final concentration of 84.1 µg/mL, but it partially inhibited platelet aggregation induced by 0.2 U/mL thrombin. At a final concentration of 14.9 µg/mL, the venom completely inhibited the aggregation of washed human platelets induced by 2.5 µg/mL collagen. In conclusion, the ability of P. baroni venom to induce hemorrhage after its injection in experimental animals likely depends on the presence of proteases (mainly metalloproteases) that degrade various components of basement membrane, such as collagen, as well as fibrinogen. Moreover, P. baroni venom inhibits collagen- and thrombin-induced platelet aggregation.