Armenuhi Moghrovyan, Lilya Parseghyan, Gohar Sevoyan, Anna Darbinyan, Naira Sahakyan, Monica Gaboyan, Zaruhi Karabekian, and Armen Voskanyan. Korean J Pain 2022;35:140-51. https://doi.org/10.3344/kjp.2022.35.2.140

Increasing concern about the use of animal models has stimulated the development of in vitro cell culture models for analysis of the biological effects of snake venoms. However, the complexity of animal venoms and the extreme synergy of the venom components during envenomation calls for critical review and analysis. The epithelium is a primary target for injected viper venom’s toxic substances, and therefore, is a focus in modern toxinology. We used the Vero epithelial cell line as a model to compare the actions of a crude Macrovipera lebetina obtusa (Levantine viper) venom with the actions of the same venom with two key enzymatic components inhibited (specifically, phospholipase A2 (PLA2) and metalloproteinases) in the bioenergetic cellular response, i.e., oxygen uptake and reactive oxygen species generation. In addition to the rate of free-radical oxidation and lipid peroxidation, we measured real-time mitochondrial respiration (based on the oxygen consumption rate) and glycolysis (based on the extracellular acidification rate) using a Seahorse analyzer. Our data show that viper venom drives an increase in both glycolysis and respiration in Vero cells, while the blockage of PLA2 or/and metalloproteinases affects only the rates of the oxidative phosphorylation. PLA2-blocking in venom also increases cytotoxic activity and the overproduction of reactive oxygen species. These data show that certain components of the venom may have a different effect within the venom cocktail other than the purified enzymes due to the synergy of the venom components.

Lilya Mushegh Parsghyan, Armenuhi Vachagan Moghrovyan, Sona Samvel Poghosyan, Milena Ashot Babajanyan, Monica Armen Gaboyan, Armen Vaghinak Voskanyan, and Anna Ashot Darbinyan. Korean J Pain -0001;0:. https://doi.org/10.3344/kjp.24301

Blunt-nosed viper venom in high doses causes severe pain, while in low doses an analgesic effect is observed. The opposite effects of different doses of venom are associated with the development of certain metabolic processes and the impact on receptors and channels of nociceptive afferent neurons. The response of the nociceptive system in the periphery and CNS depends on the dose-evoked neurochemical changes in neuronal activity. We studied the effect of various doses of MLO venom in order to understand the mechanisms of the transition of the pain effect of MLO venom into an analgesic one. Pain behavior was studied on outbred white mice at various doses of MLO venom, starting from LD₅₀ for intraplantar and in serial dilutions for intraperitoneal (1.0 and 1/5, 1/10, 1/20 and 1/30 of LD₅₀) administration during the formalin and the hot plate tests. At a dose of 1.0 LD50, experimental mice develop a strong sense of pain, which was examined in the hind paw biting/licking test. The maximum analgesic effect was expressed at 1/20 LD₅₀. To study the degree of participation of the venom’s phospholipase A2 (PLA2) enzymatic activity on pain processes, a venom with the inhibited enzymatic activity of PLA2 was tested. It was obtained, that both in the development of pain and in the analgesic effect, the enzymatic activity of PLA2 plays a significant role. It is proposed that in case of high doses the antinociceptive action of venom is masked.