Platelet dysfunction during Bothrops jararaca snake envenomation in rabbits.

Area of Science:

• Toxicology
• Hematology
• Biochemistry

Background:

• Snake envenomation is known to disrupt blood coagulation and fibrinolysis.
• Limited data exists on the specific effects of snake venom on blood platelet function.

Purpose of the Study:

• To investigate the impact of Bothrops jararaca envenomation on platelet disorders in an experimental rabbit model.
• To elucidate the mechanisms underlying venom-induced platelet dysfunction and activation.

Main Methods:

• Experimental envenomation of rabbits with Bothrops jararaca venom.
• Analysis of platelet count, fibrinogen levels, von Willebrand factor, platelet aggregation, ATP secretion, serotonin levels, and P-selectin expression.
• Flow cytometry to assess GPIIb-IIIa and LIBS-1 expression on platelets.

Main Results:

• Envenomed rabbits exhibited thrombocytopenia, hypofibrinogenemia, and elevated von Willebrand factor.
• Platelet hypoaggregation was observed in platelet-rich plasma and whole blood, but not in washed platelets.
• Decreased platelet ATP secretion and increased P-selectin expression indicated platelet activation, while GPIIb-IIIa expression showed altered epitopes.
• Intraplatelet serotonin and plasma platelet factor 4 levels remained normal.

Conclusions:

• Thrombin generated by Bothrops jararaca venom likely contributes to platelet and coagulation disorders.
• Platelet activation, evidenced by P-selectin elevation, occurs in circulating platelets.
• The findings suggest a plasma inhibitor interfering with platelet aggregation in Bothrops envenomation.