Direct nephrotoxic effects produced by venoms of Sri Lankan cobra, Russell's viper and hump nosed viper

Abstract

Nephrotoxicity is the principal cause of death following Russell's viper envenomation. Envenomation following the bite of several other snakes is also known to cause nephrotoxicity. The nephrotoxicity can be due to direct effects of venom or secondary to circulatory disturbances (eg. ischaemia), which these patients often manifest. As separating out the contributions of direct toxic effects and ischaemic effects are difficult in the in vivo situation, experiments were carried out using the kidney slice model to study and compare the direct toxic effects of venom of cobra, Russell's viper and hump nosed viper. The effect of cobra venom (CV) on rat kidney slices and the effects of Russell's viper venom (RV V) and hump nosed viper venom (HNVV) on rabbit kidney slices were examined. Healthy male animals were anaesthetized and kidneys were harvested. Kidneys were decapsulated, bisected and sliced. Rat kidney slices were incubated with CV and rabbit kidney slices were incubated with RVV and HNVV for different time periods. Rat and rabbit kidney slices were incubated with 0.9% sodium chloride as the control. At the end of each observation period kidney slices were preserved for light and electron microscopy (LM and EM). When CV was used, complete necrosis was seen in proximal and distal convoluted tubular cells (PCT and DCT). When rabbit kidney slices were incubated with RVV for 4 hours there was complete necrosis of glomeruli and PCT with the preservation of the basement membrane. LM and EM changes were mostly confined to PCT when HNVV was used. The results of this experiment provide evidence that the venoms studied produce direct damage on renal tissue. Different areas of the nephron are differentially susceptible to the effects of the three venoms.