Comparative analysis of paralytic and myotoxic effects of Crotalus durissus terrificus venom and crotoxin from different regions of Minas Gerais, Brazil.

PURPOSE: Crotalus durissus terrificus, commonly known as the South American rattlesnake, is a snake of medical relevance in Brazil. Its wide geographical distribution correlates with biochemical variations in venom composition, which can affect the typical pharmacological effects, such as neurotoxicity and myotoxicity. These effects are primarily attributed to crotoxin, the major toxic component of the venom, comprising over 50 % of its dry mass. Considering the lethality of crotali venoms from Brazil, the comparative study of their biological activities can provide subsidies for the development of a more effective antiophidic therapy, as well as guide and expand biochemical and pharmacological studies.

METHODS

We compared the toxic effects of crude Crotalus durissus terrificus venoms (1, 5, and 10 μg/mL) and their crotoxins (1 and 5 μg/mL) on mice neuromuscular preparations, through a myographic study, using venoms from four different municipalities (Carrancas, Patos de Minas, Nova Ponte and Nazareno) of Minas Gerais state, Brazil. Histological analyses were also performed to evaluate the toxic effects of these substances on the mice muscle tissues.

RESULTS

Both venoms and crotoxins induced a time- and concentration-dependent blockade over a period of 180 min. At 1 μg/mL, significant differences were observed between the venoms from Carrancas and Nazareno. Furthermore, all crotoxins displayed distinct blockade kinetics at this concentration, highlighting regional variations in composition and pharmacological activities of the venoms and toxins. Additionally, all venoms induced muscle damage at 5 and 10 μg/mL, while only CTXs from Carrancas and Nazareno caused detectable damage.

CONCLUSION

Our findings emphasize the importance of understanding the natural history and venom composition of snake populations, particularly for widely distributed species. Intraspecific venom variability may result in different clinical manifestations, which may be considered in the therapeutics of Crotalus durissus envenomation.