Renal effects promoted by myotoxins and lectins isolated from the snake venoms of Bothrops jararacusu and Bothrops moojeni. The role of cyclooxigenase and endothelin / Efeitos renais de miotoxinas e lectinas purificadas dos venenos das serpentes Bothrops jararacussu e Bothrops moojeni. Papel da ciclooxigenase e endotelina

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Acute renal failure is one of the most common systemic complications after snakebite. However, its pathogenesis remains obscure. In this study, we evaluated the renal effects of Bothrops jararacussu myotoxins I and II (Bthtx-I Lys 49 and BthtxII, Asp 49), Bothrops moojeni myotoxin I and the lectins from Bothrops moojeni and Bothrops jararacussu. Attempting to investigate the mechanisms involved in the renal effects of the mentioned toxins, we tested indomethacin, an unespecific cyclooxigenase inhibitor. Additionally, tezosentan, an endothelin receptor blocker, was used to evaluate the role of endothelin in the renal effects of Bothrops moojeni myotoxin I. All myotoxins (5 Âg/mL) and lectins (10Âg /mL) were added to the perfusion system 30 min after the beginning of each perfusion. Indomethacin (10Âg/mL) and tezosentan (10 Âg /mL) were always added 30 minutes before the tested substances. The renal effects were compared against a control group, where kidneys were perfused only with the modified Krebs-Henseleit solution. Myotoxins from Bothrops jararacussu and the lectin from Bothrops moojeni increased the perfusion pressure (C120= 110.28 Â 3.09, Bthtx I120= 171.20 Â 6.3 * ,Bthtx II120= 175.50 Â 7.20 * and BmLec120= 152.50 Â 2.10 *), the renal vascular resistance (C120= 5.46 Â 0.54, Bthtx I120= 8.62 Â 0.37 *, Bthtx II120= 8.90 Â 0.36 * and BmLec120= 7.77 Â 0.30*), the urinary flow (C120= 0.143 Â 0.008, Bthtx I120= 0.326 Â 0.048*, and Bthtx II120= 0.373 Â 0.085* ), the glomerular filtration rate (C120= 0.678 Â 0.065, Bthtx I120= 0.855 Â 0.133 *, Bthtx II120= 1.224 Â 0.282* and BmLec120= 1.037 Â 0.055*) and the sodium, potassium and chloride excretion. On the other hand, the same substances decreased the percent of renal tubular transport of sodium (C120= 79.76 Â 0.56, Bthtx I120= 62.23 Â 4.12*, Bthtx II120= 70.96 Â 2.93* and BmLec60= 77.25 Â 1.36*), potassium (C60= 66.38 Â 3.31, Bthtx I60= 55.79 Â 5.57 *, Bthtx II60= 50.86 Â 6.16* and BmLec60= 59.78 Â 3.49*). Indomethacin inhibited the renal effects induced by Bothrops jararacussu myotoxin I and Bothrops moojeni lectin, but partially blocked the effects promoted by myotoxin II and the lectin of Bothrops jararacussu, and the effects of myotoxin I of Bothrops moojeni. Tezosentan inhibited the renal effects induced by B. moojeni myotoxin I. In conclusion, prostaglandins are involved in the renal alterations induced by myotoxins and lectins purified from the snake venoms of Bothrops jararacussu and Bothrops moojeni. In addition, endothelin is the main mediator of the renal alterations promoted by Bothrops moojeni myotoxin I

ASSUNTO(S)

rim â fisiologia snake venoms - toxicity kidney - physiology lectinas tipo c fosfolipases a lectins, c-type kidney - pathology rim â patologia venenos de serpentes - toxicidade phospholipases a bothrops farmacologia geral snake venoms - pharmacology venenos de serpentes - farmacologia

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