Cardiotoxic Effects of Hemiscorpius lepturus Scorpion Venom Fractions in Rats

Background: Scorpion stings are responsible for many deaths in humans; however, the toxicity mechanisms of the venoms from many species are not well studied. We investigated the cardiotoxicity of the crude venom from H. lepturus scorpion and its isolated fractions, F-I to F-VI. Methods: The scorpion’s venom was extracted into six fractions by chromotagraphy. Healthy male Wistar rats (N=72) were equally divided into eight groups of nine: G1: Controls (0.5ml. normal saline), G2: Crude venom (1000µg/kg), G3: F-I (120µg/kg), G4: F-II (430µg/kg), G5: F-III (80µg/kg), G6: F-IV (180µg/kg), G7: F-V (60µg/kg), and G8: F-VI (130µg/kg). Blood samples were obtained by cardiac puncture at 1, 3 and 24 hours after the venom injection. The serum levels of AST, LDH, CPK, CK-MB and troponin-I were determined. Upon euthanasia, the hearts were removed from the rats and examined microscopically for histopathology. Results: In groups receiving crude venom and F-VI, we observed multifocal fragmentation of myocardial fibers, hemorrhage, degeneration and disappearance of striations in cardiac muscles as compared to the controls. The findings showed that AST and LDH activity in groups 2, 4 and 8, CPK activity in groups 2, 4, 6 and 8 and CK-MB activity and troponin-I levels in groups 2 and 8 increased significantly compared to those in the control group. Conclusions: There was evidence of significant cardiotoxicity in the group receiving crude venom and F-VI. Although alterations in the enzymatic and troponin-I levels were observed in other groups, the greatest cardiotoxicity of H. lepturus venom was caused by fraction VI.