Effects of Bungarus candidus (Malayan krait) venom on general circulation and renal hemodynamics in experimental animals

Abstract

Background: Many studies have reported the occurrence of lethal acute renal failure after snakebites. Bungarus candidus (Malayan krait) is a medically important venomous snake distributed widely throughout Southeast Asia. The best known features of systemic envenoming by B. candidus are neurotoxic. Objective: Obtain more information on effects of B. candidus venom on changes in systemic and renal hemodynamics in experimental animals. Methods: Twelve adult male New Zealand white rabbits were used to study the effect of B. candidus venom on general circulation and renal hemodynamics. An anesthetized animal was intravenously injected with B. candidus venom at a dosage of 50ìg/kg bodyweight. All changes of parameters were observed after initial post venom injection and recorded at 30 min intervals until 150 minutes after envenomation. Results: After envenomation, cardiovascular responses showed a marked decrease in mean arterial pressure within two minutes, afterwards gradually returning closely to baseline values. There were stepwise decreases in heart rate and cardiac output, while total peripheral resistance was slightly increased. The renal hemodynamics significantly decreased by glomerular filtration rate, effective renal plasma flow and effective renal blood flow, while the filtration fraction significantly increased. Envenomed animals showed a reduction in renal fraction, while renal vascular resistance stepwise increased. The plasma potassium level tended to increase. Animals showed stepwise decreases in urinary excretion of Na+, K+ and Cl-. A marked decrease in plasma calcium level was apparent at 120 minutes, while plasma creatine phosphokinase and lactate dehydrogenase levels increased at 30-120 minutes. Conclusion: A significant drop in blood pressure was attributed to a sustained fall in cardiac output, which would be associated with a reduction in heart rate. Sustained hypotension would contribute to reduction of renal blood flow, which results in decreased GFR.