Pro-inflammatory response and hemostatic disorder induced by venom of the coral snake Micrurus tener tener IN C57BL/6 mice

Abstract

Micrurus venoms are known to induce mainly neurotoxicity in victims. However, other manifestations, including hemorrhage, edema, myotoxicity, complement activation, and hemostatic activity have been reported. In order to develop a more complete pharmacological profile of these venoms, inflammatory responses and hemostasis were evaluated in C57BL/6 mice treated with a sub-lethal dose of M. t. tener (Mtt) venom (8 μg/mouse), inoculated intraperitoneally. The venom induced moderate bleeding into the abdominal cavity and lungs, as well as infiltration of leukocytes into the liver. After 30 min, the release of pro-inflammatory mediators (TNF-α, IL-6, and NO) were observed, being most evident at 4 h. There was a decrease in hemoglobin and hematocrit levels at 72 h, a prolongation in coagulation times (PT and aPTT), a decrease in the fibrinogen concentration and an increase in fibrinolytic activity. In this animal model, it was proposed that Mtt venom induces inflammation with the release of mediators such as TNF-α, in response to the toxins. These mediators may activate hemostatic mechanisms, producing systemic fibrinolysis and hemorrhage. These findings suggest alternative treatments in Micrurus envenomations in which neurotoxic manifestations do not predominate.

Contribution of endothelial cell and macrophage activation in the alterations induced by the venom of Micrurus tener tener in C57BL/6 mice

“…In addition, previous studies have shown that Mtt venom triggers an acute systemic inflammatory response within a few hours after i.p. injection into C57BL/6 mice, which may activate the hemostatic system generating a pro-coagulant state that could be followed by an anti-coagulated status characterized by reduced fibrinogen, prolonged coagulation tests and hemorrhage (Salazar et al, 2018). This study led us to evaluate the inflammatory response and hemostatic alterations induced by Mtt crude venom in an in vitro model employing liver sinusoidal endothelial cells and primary peritoneal macrophages from the same mouse strain, since these cells actively participate in inflammatory responses and hemostasis as part of innate immunity (Schouten et al, 2008;Verhamme and Hoylaerts, 2009).…”

“…At the same time, activated leukocytes express and release hemostatic factors that also modulate the innate immune response (Swystun and Liaw, 2016). In C57BL/6 mice, a pro-coagulant state was seen 24 h after Mtt venom inoculation, which reversed at 72 h to an anti-coagulant state (Salazar et al, 2018). Here, the hemostatic parameters were evaluated at earlier times to elucidate the mechanisms involved in the effects seen in vivo.…”

“…Snake venom components may induce a systemic inflammatory response, specifically proinflammatory cytokine release (Petricevich, 2004;Salazar et al, 2018). In addition, active hemostatic compounds in snake venom have been identified and isolated that can decrease the coagulability of blood, induce bleeding and associated secondary effects (Sajevic et al, 2011;White, 2005).…”

“…Micrurus envenomation is characterized by neurotoxic symptoms and may lead to death from muscle paralysis and respiratory arrest. Some reports have shown that these venoms may also contain hemorrhagic, hemostatic, hemolytic and edematogenic activities (Barros et al, 1994;Casais-e-Silva and Teixeira, 2017;Salazar et al, 2011Salazar et al, , 2018Tambourgi et al, 1994;Vivas et al, 2016). In the United States, only two species are responsible for all coral snake toxicity, Micrurus fulvius fulvius (Eastern coral snake) and Micrurus tener tener (Texas coral snake), and most of the information available rely on the Eastern coral snakebites.…”

“…In a previous article, we reported results showing that Mtt venom induced a proinflammatory response in addition to hematological and hemostatic disturbances in C57BL/6 mice that were injected intraperitoneally (i.p.) with a sub-lethal dose of this venom (Salazar et al, 2018). As the endothelium and innate immunity may participate in the disturbances seen in C57BL/6, we evaluated the inflammatory response and hemostatic alterations induced by Mtt crude venom in an in vitro model.…”