Attempt to Develop Rat Disseminated Intravascular Coagulation Model Using Yamakagashi (Rhabdophis tigrinus) Venom Injection

Abstract

Disseminated intravascular coagulation, a severe clinical condition caused by an underlying disease, involves a markedly continuous and widespread activation of coagulation in the circulating blood and the formation of numerous microvascular thrombi. A snakebite, including that of the Yamakagashi (Rhabdophis tigrinus), demonstrates this clinical condition. Thus, an animal model using Yamakagashi venom was constructed. Yamakagashi venom was administered to rats, and its lethality and the changes in blood coagulation factors were detected after venom injection. When 300 μg venom was intramuscularly administered to 12-week-old rats, (1) they exhibited hematuria with plasma hemolysis and died within 48 h; (2) Thrombocytopenia in the blood was observed in the rats; (3) irreversible prolongation of prothrombin time in the plasma to the measurement limit occurred; (4) fibrinogen concentration in the plasma irreversibly decreased below the measurement limit; and (5) A transient increase in the plasma concentration of D-dimer was observed. In this model, a fixed amount of Rhabdophis tigrinus venom injection resulted in the clinical symptom similar to the human pathology with snakebite. The use of the rat model is very effective in validating the therapeutic effect of human disseminated intravascular coagulation condition due to snakebite.

Attempt for a Recombinant Thrombomodulin Alpha Treatment in a Rat Disseminated Intravascular Coagulation Model Using Yamakagashi (Rhabdophis tigrinus) Venom

“…Therefore, a confirmation experiment was conducted using the in vivo measurement system of rTM. We used a previously described rat DIC model as a system for measuring the activity of R. tigrinus venom in vivo [ 23 ]. Briefly, 1 mg/kg of rTM was administered intravenously to this measurement system at 2, 0.5, 0.33, and 0.17 h after venom administration.…”

“…Compared with the effect of R. tigrinus antivenom in the in vivo experimental system, the life-saving effect on rats was similar. In addition, a comparison of the changes in blood coagulation markers in life-saving rats that recovered from thrombocytopenia, prolongation of PT, and decreased FIB concentrations was observed [ 23 ]. The difference in the effects of rTM and R. tigrinus antivenom in the in vivo experimental system appeared in the amount of D-dimer as a blood coagulation marker.…”

“…The difference in the effects of rTM and R. tigrinus antivenom in the in vivo experimental system appeared in the amount of D-dimer as a blood coagulation marker. Antivenom had little effect on the appearance of D-dimer, but rTM significantly suppressed the appearance of D-dimer [ 23 ]. D-dimer is normally undetectable or only detectable at a very low level unless the animal body is forming and breaking down significant blood clots.…”

Rhabdophis tigrinus (Yamakagashi) Bites in Japan Over the Last 50 Years: A Retrospective Survey

“…However, two fatalities occurred in elderly people, both of whom were confirmed to have died from complications related to R. tigrinus bites. No fatalities have been observed among patients treated with the antivenom, which suggests that it is important to diagnose R. tigrinus bites in patients with unexplained severe coagulopathy ( 17 ) in the early phase of the clinical course. Raising awareness not only in the departments of emergency and intensive care but also in the fields of pediatrics and neurosurgery is imperative.…”

Rodent Lethality Models Are Problematic for Evaluating Antivenoms for Human Envenoming

“…In a recent study, acute kidney injury was not able to be replicated in rats with sub-lethal doses of D. russelii venom suggesting it to be a poor model for venom-induced acute kidney injury (Wijewickrama et al, 2018). VICC, AKI and thrombocytopaenia only occurred with experimental venom doses that were unrealistically higher than what is observed in actual human envenomings, making it difficult to match the reallife envenoming scenarios in humans (Tan et al, 2012;Romanelli et al, 2021;Thomazini et al, 2021;Yamamoto et al, 2021).…”