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Assessment of the enzymatic, neuromuscular and hemostatic action of Crotalus durissus ruruima (Viperidae: Crotalinae) venom and neutralization by commercial antivenom

Grant number: 22/05878-3
Support Opportunities:Scholarships in Brazil - Scientific Initiation
Effective date (Start): October 01, 2022
Effective date (End): September 30, 2023
Field of knowledge:Biological Sciences - Pharmacology - Toxicology
Principal Investigator:Rafael Stuani Floriano
Grantee:Poliana de Jesus Demico
Host Institution: Pró-Reitoria de Pesquisa e Pós-Graduação. Universidade do Oeste Paulista (UNOESTE). Presidente Prudente , SP, Brazil


Envenomation by Crotalus (rattlesnakes) is characterized by clinical manifestations such as local and systemic myonecrosis, neuromuscular paralysis, renal injury, hemorrhage, coagulopathy, and hypotension. In Brazil, the treatment for crotales envenomation is conditioned to antivenom produced from the subspecies C. durissus terrificus venom (distributed in South and Southeastern regions of Brazil), there being no study of its neutralizing efficacy on the neuromuscular e hemostatic effects of the envenomation by C. durissus ruruima (subspecies geographically separated of C. d. terrificus and restricted to State of Roraima, Brazil). In this project, we propose to assess the protective action of the monovalent serum produced by Instituto Butantan (anti-C. d. terrificus) on the enzymatic, neuromuscular e hemostatic action of C. d. ruruima venom in experimental models in vitro and ex vivo. Initially, we will carry out a comparative protocol of enzymatic kinetics for phospholipase A2, caseinolytic, esterase and L-amino acid oxidase of the C. d. terrificus and C. d. ruruima venoms to determine the activity level of each major enzymatic group of these venoms; it will be used colorimetric methods read in a spectrophotometer. For ex vivo protocols, the inhibitory action of the anticrotalic serum on the hemostatic activity of the C. d. terrificus and C. d. ruruima venoms will be determined from the minimal coagulant dose, activation of prothrombin and activated partial thromboplastin, and thrombin-like activity in rat citrated plasma using commercial kits for coagulometry. In addition, the inhibitory action of the antivenom will be assessed on the neuromuscular effect of the C. d. terrificus and C. d. ruruima venoms in mouse isolated nerve phrenic diaphragm preparation mounted in a multifunction myographic system. The results of this study will contribute to understand the neutralizing potential of the anticrotalic serum on the major effects of the envenomation by C. durissus subspecies geographically separated from the precursor subspecies of the antivenom.(AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
COUCEIRO, FERNANDA Y. G. M.; DEMICO, POLIANA J.; DIAS, SAMUEL R.; OLIVEIRA, ISABELE N.; PACAGNELLI, FRANCIS L.; SILVA, ELISANGELA O.; SANT'ANNA, SAVIO S.; GREGO, KATHLEEN F.; MORAIS-ZANI, KAREN; TORRES-BONILLA, KRISTIAN A.; et al. Involvement of phospholipase A2 in the neuromuscular blockade caused by coralsnake (Micrurus spp.) venoms in mouse phrenic nerve-diaphragm preparations in vitro. Toxicon, v. 234, p. 8-pg., . (20/04287-6, 20/07268-2, 23/01961-6, 22/05878-3)

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