Rabbit antivenom efficacy against myotoxic and neurotoxic activities OF Bothrops jararacussu venom and bothropstoxin-I

Y. Oshima-Franco(1), G. B. Leite(1), A. A. Valério(1), S. Hyslop(1), S. Andriao-Escarso(3), J. R. Giglio(3), J. Prado-Franceschi(1), M. A. Cruz-Höfling(2), L. Rodrigues-Simioni(1)

(1)Department of Pharmacology and (2)Department of Histology and Embryology, State University of Campinas (UNICAMP), 13083-970, Campinas, SP, Brazil; (3)Department of Biochemistry, Faculty of Medicine, University of São Paulo (USP), 14049-900, Ribeirão Preto, SP, Brazil.

ABSTRACT:Bothrops jararacussu venom and its major toxin bothropstoxin-I (BthTX-I) possess myotoxic and neurotoxic properties. The efficacy of a rabbit antivenom raised against B. jararacussu venom in the neutralization of physiological, biochemical, and morphological changes induced by the venom and its major toxin BthTX-I was studied in mouse isolated phrenic nerve-diaphragm (PND) and extensor digitorum longus (EDL) preparations. The times required for 50% neuromuscular blockade in PND and EDL preparations for venom were 70+11.5 (S.E.M., n=5) min and 58+8 (n=16) (50 µg/mL), and for BthTX-I 31+6 (n=3) min and 30+3 (n=5) min (20 µg/mL), respectively. After 120 min incubation, creatine kinase (CK) concentrations in solution containing the EDL preparations were 3464+346 U/L after exposure to venom (50 µg/mL, n=5) and 3422+135 U/L to BthTX-I (20 µg/mL, n=4), respectively. Rabbit antivenom dose-dependently neutralized venom and toxin-induced neuromuscular blockade in both preparations and effectively prevented venom and toxin-induced CK release from EDL. Histological analysis showed that rabbit antivenom neutralized morphological damage caused by B. jararacussu venom and BthTX-I in EDL preparations. These results indicate that rabbit antivenom effectively neutralized the biological activities of B. jararacussu venom and BthTX-I.

KEY WORDS: Bothrops venom, myotoxin, neutralization, neuromuscular junction, histological analysis, Bothrops jararacussu.

CORRESPONDENCE TO:

L. Rodrigues-Simioni – Departamento de Farmacologia, Faculdade de Ciências Médicas – Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6111, 13083-970, Campinas, SP, Brasil Phone: 55 19 3788-7482 / Fax: 55 19 3289 2968 Email simioni@obelix.unicamp.br