Experimental model for removal of snake venom via hemoperfusion in rats

Objective To examine the efficiency of hemoperfusion in removing South American rattlesnake (Crotalus durissus terrificus) venom from rats compared with neutralization by antivenom. Design An exploratory experimental investigation in rats involving the injection of snake venom with or without subsequent hemoperfusion or antivenom administration. Setting Basic animal research laboratory in a private university. Animals Normal, healthy male Wistar rats (0.29‐0.40 kg, 3‐6 months old) from a commercial breeder. Interventions Four experimental groups of randomly allocated rats (n = 3/group) were studied: Group 1: rats were injected with a single dose of venom (5 mg/kg, IM, in the right thigh) with no other treatment; blood samples were collected minutes before death to determine leukocyte, platelet, and erythrocyte counts; Group 2 (Control): rats underwent hemoperfusion alone for 60 min using a hemoperfusion cartridge designed for protein adsorption (by granulated charcoal) and protein precipitation (by tannic acid); Group 3 (Venom + antivenom): rats were injected with venom (5 mg/kg, IM) and, 10 min later, were treated with antivenom at the venom:antivenom ratio recommended by the manufacturer; Group 4 (Venom + hemoperfusion): Rats were injected with venom (5 mg/kg, IM) and, 10 min later, were hemoperfused for 60 min. In groups 2‐4, blood samples were collected for leukocyte, platelet, and erythrocyte counts 24 h after venom. Measurements and Main Results Rats injected with venom alone (Group 1) developed signs of neurotoxicity and ataxia and died in 9.0 ± 0.43 h but showed no changes in leukocyte or erythrocyte counts. In contrast, there were no deaths in groups 2‐4. The lack of deaths in Groups 3 and 4 indicated that antivenom and hemoperfusion, respectively, protected against the lethal effects of the venom. Conclusions Hemoperfusion with a double‐action hemoperfusion cartridge capable of protein adsorption and precipitation protected rats against C. d. terrificus venom.