Functional alterations of rabbit erythrocytes induced by Loxosceles gaucho venom.

Loxoscelism is the syndrome caused by the brown spider Loxosceles gaucho bite in humans. Its effect on erythrocytes has been studied in humans, rabbits, pigs and guinea pigs. In this study, the damage that the L gaucho spider venom causes to the structure and function of erythrocytes in vivo was investigated in rabbits. Before and after the rabbits were envenomed, membrane proteins were studied through polyacrylamide gel electrophoresis and membrane function was ascertained using the osmotic fragility test, together with the highly sensitive technique of ektacytometry. Six New Zealand rabbits were inoculated by intradermal injection into the dorsal region (10 microg of venom/kg of body weight in 0.2 mL of saline). Blood was collected at 24, 48, 72 and 120 h after inoculation. The membrane protein study did not reveal any alteration in their relative band concentrations, but the osmotic fragility test showed increased hemolysis in slightly hypotonic sodium chloride solutions (at 0.6 and 0.55%). In addition, the ektacytometer study revealed greater deformability to increasing shear stress on the order of 3-30 Pascals when compared with controls, showing that the L gaucho venom does in fact alter red cell function.