HEMATOLOGICAL ALTERATIONS INDUCED EXPERIMENTALLY IN RABBITS BY THE VENOM OF THE SPIDER BROWN Loxosceles gaucho

Tavares, F.L.(1), Barbaro, K.C.(2), Sousa-e-Silva, M.C.C.(1), Santoro, M.L.(1), Sano-Martins I.S.(1)

(1)Laboratóriode Fisiopatologia do Instituto Butantan, (2)Laboratório de Imunopatologia do Instituto Butantan, SP-Brazil.

Human accidents by Loxosceles sp, brown spider, cause dermonecrosis and occasionally intravascular hemolysis, disseminated intravascular coagulation (DIC), renal failure and death. The aim of this work was to characterize in rabbits the hematologic responses induced by the administration (i.d.) of Loxosceles gaucho venom and the evolution of systemic reaction. At 3, 24, 48, 72 and 120 hours after the i.d injection of crude venom (10µg/kg), animals were anesthetized and the blood collected from the carotid artery after a surgical procedure. The results showed an initial leukopenia (3 and 24 hours), at  72 hours an intense polymorphonuclear leukocytosis. A significant thrombocytopenia was observed at 3 and 24 hours whereas thrombocytosis occurred in 120 hours. Erythrocytes count, packed cell volume, and hemoglobin levels were decreased at 72 and 120 hours. Haptoglobin and fibrinogen were increased, but hyperproteinemia was not observed, wich might be compensated by hemodilution, explaining the decreased of the hematological parameters. In addition, coagulation factors V, VII, VIII, IX, X and XI were increased at 120 hours. Bilirrubins and plasma hemoglobin, aspartate aminotransferase, alanine aminotransferase, glutamil gamatransferase, albumin, blood urea nitrogen and creatinine were within normal range. Our present results showed that the rabbits develops no systemic reaction of loxoscelism, as observed in humans cases, since intravascular hemolysisand DIC were not verified. However, the thrombocytopenia and leukopenia in the initial time intervals are probably related to the establishment of the lesion, confirming that rabbits are a good model for the study of cutaneous necrosis of loxoscelism.

Supported by: FAPESP

CORRESPONDENCE TO:

Maria Cristina Cirillo de Sousa e Silva, Avenida dos eucaliptos 217 apto 133, SP, CEP: 04517-050, Brasil, Email: mccss@yahoo.com