Effect of RVV-X and RVV-X-specific antivenom on renal functions and coagulopathy in rats

Abstract

Acute renal failure (ARF) is the most frequent and a serious complication in Russell’s viper bite victims. Russell's viper venom-factor X activator (RVV-X) has been identified as a main procoagulant enzyme involving coagulopathy, which might be responsible for changes in renal hemodynamics and functions. In this study, RVV-X was purified four fold from crude Russell's viper venom (cRVV) using a Sephadex G-100 gel filtration and then a Q-sepharose anion exchange column chromatography with approximately 5% yield. Purified RVV-X had coagulant and fibrinogenolytic functions. Then, we studied the effects of purified RVV-X and cRVV on DIC, renal hemodynamics and functions, as well as the accompanying histopathological changes in Sprague-Dawley rats (SD) (n = 6). The plasma D-dimer level was determined after intravenous injection of equipotent sublethal dose of cRVV (7 μg/kg) and purified RVV-X (1.75 μg/kg) in rats at various times. The plasma D-dimer levels increased and reached a peak at 10 min, declined temporarily and then reached another peak at 30 min after purified RVV-X injection, while plasma D-dimer levels of rats given cRVV gradually increased to reach a peak at 45 min. The higher plasma D-dimer level at 45 min of rats given crude venom is supposed to be due to the other coagulants in crude venom promoting coagulopathy. Changes in renal hemodynamic and function were evaluated using mean arterial pressure (MAP), glomerular filtration rate (GFR), effective renal plasma flow (ERPF), effective renal blood flow (ERBF), renal vascular resistance (RVR), and fractional excretion of all electrolytes (FE[subscript E]). After 10 min rat receiving both cRVV and purified RVV-X significantly decreased GFR, ERPF, ERBF and significantly increased RVR when compared to the normal saline control group. These changes correlated to the kidney lesions. There were no significant differences in renal hemodynamic and function parameters in rats injected with cRVV and purified RVV-X. These findings indicated that RVV-X plays an important role in renal hemodynamic and function changes through DIC. In addition, we established the rabbit anti-recombinant proteins IgG antibodies recognizing purified RVV-X but did not inhibit factor X activator activity of purified RVV-X. However, these rabbit anti-recombinant proteins IgG antibodies cross reacted with Cryptelytrops albolabris and Calloselasma rhodostoma venoms. Further studies are needed to use these antibodies to further develop the affinity column for purification of snake molecules for drug discovery.