We studied the neutralisation of Sri Lankan Russell's viper (Daboia russelii) and Australian mulga snake (Pseudechis australis)
venom-induced
myotoxicity by Indian (Vins and Bharat) and Australian (Seqirus) polyvalent
antivenoms, using the in vitro chick biventer skeletal muscle preparation. Prior addition of Bharat or Vins
antivenoms abolished D. russelii
venom (30 µg/mL)-mediated inhibition of direct twitches, while Australian polyvalent
antivenom was not protective. Bharat
antivenom prevented, while Vins and Australian polyvalent
antivenoms partially prevented, the inhibition of responses to exogenous KCl.
Myotoxicity of Mulga
venom (10 µg/mL) was fully neutralised by the prior addition of Australian polyvalent
antivenom, partially neutralised by Vins
antivenom but not by Bharat
antivenom. Although the
myotoxicity of both
venoms was partially prevented by homologous
antivenoms when added 5 min after the
venom, with an increasing time delay between
venom and
antivenom, the reversal of
myotoxicity gradually decreased. However,
antivenoms partially prevented
myotoxicity even 60 min after
venom. The effect of
antivenoms on already initiated
myotoxicity was comparable to physical removal of the toxins by washing the bath at similar time points, indicating that the action of the
antivenoms on
myotoxicity is likely to be due to trapping the toxins or steric hindrance within the circulation, not allowing the toxins to reach target sites in muscles.