Bothrops fonsecai snake venom biological effects and the use of commercial bothropic antivenom as pharmacological tool

Author(s)

Rita de Cássia de Oliveira Collaço

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2014-07-29

Examining board members

Lea Rodrigues Simioni; Elen Cristina Teizem Landucci; Stella Regina Zamuner

• Advisor: Lea Rodrigues Simioni

Abstract

Bothropic snake venoms are characterized for a marked local damage associated to systemic effects. Bothrops fonsecai is a Brazilian pit viper of restrict distribution (Atlantic Forest at high altitude regions) and its venom has been poorly studied but is known it has phospholipases A2, metalloproteases (P-I and P-III) and serine proteases. Experimental assays using commercial bothropic antivenom to neutralize the bothropic venom activities allows clinical responses (snakebites treatment) and also is a pharmacological tool to evaluate different venoms composition through venom:antivenom cross-reactivity. Thinking in all this, the aim of this work were the B. fonsecai venom toxicity analysis through the in vitro neuromuscular junction action, the myotoxic, hemorrhagic, edema-forming and coagulant activities, as well its biochemical characterization. The neutralization of those activities by the commercial bothropic antivenom and the comparison of venom:antivenom bindings (Bothrops fonsecai venom : Commercial and specific antivenoms) by SE-HPLC and immunoblotting were also evaluated. B. fonsecai venom had a high phospholipasic activity and this probably is the major responsible for neuromuscular blockade and miotoxicity caused by this venom. This activity is also one of edema-forming activity mediator (with metalloproteases P-I). The partial inhibition of this activity with both proportions (5:1 and 5:2) corroborates the partial neuromuscular blockade and edema neutralization; in contrast total the inhibition of miotoxicity allows us to suppose that the catalytic PLA2 are not the major responsible for the miotoxicity. The venom also showed a low metalloprotease activity (caused principally by P-I once is more abundant on this venom) and was not significantly inhibited by commercial bothropic antivenom at both proportions; these enzymes (especially P-III) also induced hemorrhage totally inhibited by commercial bothropic antivenom. The esterase and coagulant activities of this venom are caused mainly by serine-proteases; the commercial antivenom neutralization was more potent at 5:2 than 5:1 proportion. The commercial antivenom presented cross-reactivity in all tested activities but its low affinity with B. fonsecai venom indicates that the venom composition is a quite different than the composition of snake venoms used to produce the commercial antivenom, specially catalytic phospholipases, metalloproteases P-I and serine proteases (AU)

• FAPESP's process: 12/06165-9 - Study of biological activities induced by Bothrops fonsecai snake venom and the uso of commercial bothropic antivenom as a pharmacological tool.
• Grantee: Rita de Cássia de Oliveira Collaço
• Support Opportunities: Scholarships in Brazil - Master