Pig as an experimental model for the study of snake venom induced local tissue necrosis

Local tissue necrosis due to snake envenoming has resulted in considerable chronic disability. Specific antivenom, though highly useful in systemic poisoning, is not very effective in preventing the local tissue damages which occur within minutes of envenomation. Most of the studies on local tissue necrosis have been done in rodents whose skin structures are significantly different from human skin structure. In this study, pig, which is similar to human in this respect, was used as an experimental model for the study of local tissue damage caused by snake venom.An intradermal (i.d.) injection of Calloselasma rhodostoma (CR) venom induced induration and hemorrhage at the same injection site, the areas of which could be estimated at 30–45 min and at 4 h after injection, respectively. Both the hemorrhage and induration were dose-dependent and a total of 24 data points of each assay per pig could be obtained. Catheterization of the jugular vein for gentle serial blood collection could be performed without any hematologic sequelae. Venom injected subcutaneously induced myonecrosis as demonstrated by the increment of serum creatine kinase (CK) level which peaked at 23 h. Furthermore, biopsies at varying distances and depths around the venom injection sites could be made within seconds of injection to study the pathological changes caused by snake venom. These results demonstrated that pig should be a useful animal model for the quantitation, pathogenesis and wound healing studies of snake venom induced local tissue necrosis, and for the search for effective treatment modality.