Direct Effect of Russell's Viper Venom (Rvv) on Renal Hemodynamics, Urinary Enzymes and Thromboxane B2 in Dogs

Abstract

In this study, we assessed the effects of RVV on renal hemodynamics, urinary enzymes, plasma and urinary Tx in 7 dogs during and after a 40-min intrarenal arterial infusion of RVV (1.25 μg/kg/min). All parameters were determined before and at 20, 40 and 60 min after the beginning of RVV. The urinary enzymes measured included N-acetyl-ß-D-glucosaminidase (NAG). γ-glutamyl, transpeptidase (γ-GT), alanine-aminopeptidase(AAP) and ß-galactosidase (GAL). Plasma and urinary Tx were measured by radioimmunoassay after extraction and purification steps.

As compared with the control stage, significant change was observed for a decrease in the mean arterial pressure (MAP) during the first 20 min after RVV administration (128.4 ± 7.7 vs. 118 ± 10.2 mm Hg. mean±SE, p < 0 .025) as well as the fractional excretion of sodium (), potassium ( ), and chloride () (p <0.05). The heart rate (HR), renal blood flow (RBF) and glomerular tiltration rate (GFR) did·not change significantly for all period of observation. Urine flow (V) increased by approximately 15.4-65.4% in 5 dogs and decreased 6.6-32.9% in 2 dogs.  increased significantly 40 min after the commencement of RVV infusion (727 ±301 VS. 1484 ± 386 units/min, p < 0.005). A 7-to 9-fold elevation of  was detected for all periods of observation but  was significantly increased during the first 20 min after RVV infusion

This study showed : (1) The changes of RBF and GFR could not explain the rise of V, excretion of electrolytes and . They should rather be accounted for by direct tubular dysfunction (2) Plasma increased in parallel with  suggesting an augmented synthesis of and/or disturbance of active reabsorption of  by tubular cells.(3) The elevation of NAG indicated direct nephrotoxicity of RVV.