Biochemical study on cardiotoxic effects of Mesobuthus eupeus scorpion venom and the role of antivenom and carvedilol in rats

Mesobuthus eupeus is an indigenous scorpion species in Southwest Iran which is responsible for the majority of scorpion sting cases in Khuzestan province. To conduct this research a total of 75 Wistar male rats were divided into 5 equal groups randomly. Group 1 (control); Group 2: M. eupeus venom was administered with a dose of 1 mg/kg IP. Group 3: Venom + 0.5 ml of polyvalent antivenom intramuscularly, 30 minutes after envenomation. Group 4: Venom + 5 mg/kg of carvedilol 30 minutes after envenomation IP. Group 5: Venom + 0.5 ml of polyvalent antivenom + 5 mg/kg of carvedilol 30 minutes after envenomation IP. Blood samples were collected by cardiac puncture at 8, 24, and 48 hours after saline/venom injection from anesthetized rats. Heparinized plasma was isolated to measure cardio-related biochemical parameters, including the activity of CPK, LDH, and AST and troponin-I levels were measured by routine methods. The results showed that the activity of the enzymes of CPKMB, LDH, AST, and also troponin-I as a specific index of heart damage elevated at different times following venom injection compared with the control group. Even though the administration of anti-venom following venom injection at different times significantly reduced the activity of these enzymes and also troponin-I levels, but the level of these indicators was still higher than the control group. Carvedilol administration had no significant effect on reducing the activity of the above-mentioned factors. Meanwhile, the combined administration of carvedilol and anti-venom following venom injection had similar results with the antivenom group. This result may relate to the dose and its frequency of carvedilol use.