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.

Controle termo-higrométrico microambiental para animais de laboratório por meio de tecnologia termoelétrica: estudo experimental para roedores de laboratório / Termohigrometric microenvironmental control for laboratory animals through thermoelectric technology: experimental study for laboratory animals

Um condicionador de ar para biotérios foi montado com módulos termoelétricos de efeito Peltier. Para troca térmica foram empregados dissipadores externos a água, obtendo-se Δt de 21 ºC, rendimento de 46,02%, consumo de 524 W/h. A simulação matemática de operação, com mistura de ar não condicionado, mostrou que o sistema pode servir a aproximadamente 137 microisoladores padrão rato com dissipação externa a água. O sistema termoelétrico mostrou ainda, precisão de ± 0,1 ºC, nas temperaturas experimentais, o que é impossível num sistema de freon. Foram ensaiadas as seguintes temperaturas: 22º, 24º, 26º, 28º e 30 ºC, obtendo sempre estabilidade e precisão, independentemente da temperatura ambiental onde o equipamento estava em operação.

An air conditioner for animal facilities was mounted with thermoelectric modules of Peltier effect. For heat exchange, a water dissipation system was employed.The air temperature difference (Δt) was 21 ºC, the performance was 46.02% and the power consumption was 524 W/h. The mathematical simulation of operation, with mixture of no conditioned air showed that the system can serve approximately 137 standard mouse microisolators, with water dissipation system. The thermoelectric system also showed an accuracy of ± 0.1 ºC at the experimental temperatures, which is impossible in a system of Freon Gas. We tested the following temperatures: 22º, 24º, 26º, 28º and 30 ºC, always getting stability and accuracy at any outside temperature.