In Vitro Toxicity of Chinese Russell's Viper () Venom and Neutralisation by Antivenoms.

(Russell's viper) is a highly venomous and medically important snake in China, as well as much of Asia. There is minimal information on the pharmacological activity of the venom of the Chinese species, and currently no commercially available specific antivenom in China. This has led to the use of non-specific antivenoms to treat envenomation. In this study, the in vitro neurotoxicity and myotoxicity of venom was examined and the efficacy of four antivenoms was investigated, including the recently developed Chinese monovalent antivenom (C-DsMAV) and three commercially available antivenoms (Thai (Thai-DsMAV) monovalent antivenom, monovalent antivenom (DaAV), and monovalent antivenom (GbAV). venom (10-30 µg/mL) caused the concentration-dependent inhibition of indirect twitches in the chick biventer cervicis nerve muscle preparation, without abolishing contractile responses to exogenous agonists ACh or CCh, indicating pre-synaptic neurotoxicity. Myotoxicity was also evident at these concentrations with inhibition of direct twitches, an increase in baseline tension, and the partial inhibition of ACh, CCh, and KCl responses. The prior addition of C-DsMAV or Thai-DsMAV prevented the neurotoxic and myotoxic activity of venom (10 µg/mL). The addition of non-specific antivenoms (GbAV and DaAV) partially prevented the neurotoxic activity of venom (10 µg/mL) but failed to neutralize the myotoxic effects. We have shown that venom exhibits in vitro weak presynaptic neurotoxicity and myotoxicity, which can be prevented by the pre-addition of the Chinese and Thai Russell's viper antivenoms. Non-specific antivenoms were poorly efficacious. There should be further development of a monospecific antivenom against envenomation in China.