Study of the Acute Toxicity of Scorpion Leiurus macroctenus Venom in Rats.

Background: The expansion of the territory of human habitation leads to inevitable interference in the natural range of distribution of one or another species of animals, some of which may be dangerous for human life. Scorpions-the Arachnida class and order Scorpiones-can be considered as such typical representatives. Scorpions of the Buthidae family pose a particular danger to humans. However, LD₅₀ has not yet been defined for many species of this family, in particular, new representatives of the genus Leiurus. Leiurus macroctenus is a newly described species of scorpion distributed in Oman, and the toxicity of its venom is still unknown. Estimating the LD₅₀ of the venom is the first and most important step in creating the antivenom and understanding the medical significance of the researched animal species. The purpose of this study was to determine the lethal dose (LD₁₀₀), the maximum tolerated dose (LD₀), and the average lethal dose (LD₅₀) in rats when using Leiurus macroctenus scorpion venom.

Methods and results: 15 sexually mature scorpions were used in the study, which were kept in the same conditions and milked by a common method (electric milking). For the study, 60 male rats were used, which were injected intramuscularly with 0.5 ml of venom solution with a gradual increase in the dose (5 groups, 10 rats in each), and 10 rats were injected intramuscularly with physiological solution as control group. LD calculations were done using probit analysis method in the modification of the method by V.B. Prozorovsky. The LD₀ of Leiurus macroctenus scorpion venom under the conditions of intramuscular injection was 0.02 mg/kg, LD₁₀₀ was 0.13 mg/kg, and LD₅₀ was 0.08 ± 0.01 mg/kg.

Conclusions: The analysis of scientific publications and other sources of information gives reason to believe that Leiurus macroctenus has one of the highest values of LD₅₀ not only among scorpions but also among all arthropods in the world. All these point to the significant clinical importance of this species of scorpion and require further research that will concern the toxic effect of its venom on various organ systems. Determining the LD50 of the venom for new scorpion species is crucial for creating effective antivenoms and understanding the medical implications of envenomation by this species.