Abstract
Neutralization of hyperalgesia induced by Bothrops jararaca and B. asper venoms was studied in rats using bothropic antivenom produced at Instituto Butantan (AVIB, 1 ml neutralizes 5 mg B. jararaca venom) and polyvalent antivenom produced at Instituto Clodomiro Picado (AVCP, 1 ml neutralizes 2.5 mg B. aspar venom). The intraplantar injection of B. jararaca and B. asper venoms caused hyperalgesia, which peaked 1 and 2 h after injection, respectively. Both venoms also induced edema with a similar time course. When neutralization assays involving the independent injection of venom and antivenom were performed, the hyperalgesia induced by B. jararaca venom was neutralized only when bothropic antivenom was administered iv 15 min before venom injection, whereas edema was neutralized when antivenom was injected 15 min or immediately before venom injection. On the other hand, polyvalent antivenom did not interfere with hyperalgesia or edema induced by B. asper venom, even when administered prior to envenomation. The lack of neutralization of hyperalgesia and edema induced by B. asper venom is not attributable to the absence of neutralizing antibodies in the antivenom, since neutralization was achieved in assays involving preincubation of venom and antivenom. Cross-neutralization of AVCP or AVIB against B. jararaca and B. asper venoms, respectively, was also evaluated. Only bothropic antivenom partially neutralized hyperalgesia induced by B. asper venom in preincubation experiments. The present data suggest that hyperalgesia and edema induced by Bothrops venoms are poorly neutralized by commercial antivenoms even when antibodies are administered immediately after envenomation.
Highlights
Antivenoms of equine or ovine origin constitute the only effective treatment of snakebite envenomation [1]
Neutralization of hyperalgesia and edema induced by Bothrops jararaca venom The intraplantar injection of BjV (5 μg/ paw) into the rat hind paw caused a signifi
The present results further demonstrate the complete ineffectiveness of these antivenoms in neutralizing the local edema and hyperalgesia induced by B. asper and B. jararaca venoms when antivenoms are administered to rats after envenomation
Summary
Antivenoms of equine or ovine origin constitute the only effective treatment of snakebite envenomation [1]. The use of these products has greatly contributed to the reduction of mortality owing to their effectiveness in the neutralization of life-threatening, systemically acting toxins present in snake venoms [2,3,4]. Randomized controlled clinical trials have demonstrated that antivenoms are highly effective in halting systemic bleeding, coagulopathies and other cardiovascular disturbances due to envenomations by snakes of the family Viperidae in Latin America [3,5,6,7]. Clinical observations indicate that local tissue damage is only partially halted by antivenoms [2,3,13]
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