Renal Physiopathology Laboratory, Division of Nephrology, Department of Medicine, Department of Pathology, and Division of Hematology, Department of Medicine, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil
Acute renal failure (ARF) has been frequently reported after bites from the Viperidae snake family. The lack of a reproducible animal model has hampered the study of renal damage mechanisms. Intravenous injection of rats with 0.4 mg/kg of Bothrops jararaca venom produced functional and morphologic changes similar to those observed in human snakebite-induced ARF. There was an acute and significant decrease in the glomerular filtration rate, diuresis, and renal plasma flow. Serum fibrinogen levels decreased significantly. There was intravascular hemolysis, as shown by a significant decrease in hematocrit, and an increase in plasma lactate dehydrogenase levels and free hemoglobin. Blood pressure and serum creatine phosphokinase levels were not affected. Light and electron microscopy showed massive fibrin deposition in glomerular capillaries, proximal and distal tubular necrosis, and hemolyzed red blood cell casts in renal tubules. Based on these findings, a model of snakebite-induced ARF was achieved. Ischemia related to glomerular coagulation and intravascular hemolysis were the most important pathogenic factors causing a decrease in the glomerular filtration rate, although a direct venom nephrotoxicity cannot be excluded.