Estudo dos efeitos renais e vasculares do veneno da serpente Crotalus durissus cumanensis e crotoxina

• Autor(a) principal: Pereira, Ticiana Praciano
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/4281
• topic: Crotoxina; Rim; Venenos de Crotalídeos

Ophidian accidents involving species of the genus Crotalus, are usually serious and frequently fatal due to the frequency of acute renal failure. Unfortunately, there have been few studies of the toxinologic effects of Crotalus durissus cumanensis venom. The renal effects of the venom used in this study were observed by perfusion of isolated kidneys. Infusion of C. d. cumanensis venom (10 µg/mL) produced an increase in perfusion pressure (PP) and renal vascular resistance (RVR). Urinary flow (UF) and glomerular filtration rate (GFR) were reduced. The venom was able to decrease the percentage of sodium tubular transport (%TNa+) and the percentage of chloride tubular transport (%TCl-). In kidneys perfused with (10 µg/mL) crotoxin, there were no significant changes in PP or RVR. The GFR decreased, while the UF increased. In contrast with whole venom, crotoxin reduced %TNa+, %TK and %TCl-. Analysis of the cytotoxic effects of Crotalus durissus cumanensis venom and crotoxin on renal tubular MDCK cells was performed by the MTT method. The venom promoted a concentration-dependent cytotoxic effect with an IC50 value of 5.38 µg/mL. In aortic rings precontracted by phenylephrine (Phe; 0.1 mM) with intact endothelium, C. d. cumanensis venom (0.1–30.0 µg/mL) resulted in an increased maximal contraction up to 130.0 ± 6.6% at a concentration of 30.0 µg/mL. In contrast, in endothelium denuded rings, vasocontraction was reduced in a concentration-dependent manner to 66.7 ± 4.9% (50.0 µg/mL). The effect was similar in the case of potassium-induced contraction (K+; 40 mM), in which there was a significant increase in the contraction of endothelium intact rings up to 115.6 ± 4.9% (30.0 µg/Ml) and a vasorelaxant effect (70.9 ± 4.7%) at a dose of 50.0 µg/mL after removal of the endothelium. In conclusion, C. d. cumanensis venom and crotoxin cause toxicity in isolated kidneys, however, only the whole venom has a cytotoxic effect on renal tubular cells. In aortic ring assays, whole venom causes endothelium dependent vasoconstriction. It is suggested that the toxic effects produced by the venom of Crotalus durissus cumanensis in kidney and isolated aorta, probably due to the participation of other fractions or a synergism of the components that make up the total venom.