HEMORRHAGIC TOXINS FROM RATTLESNAKE (CROTALUS-ATROX) VENOM - PATHOGENESIS OF HEMORRHAGE INDUCED BY 3 PURIFIED TOXINS

Abstract

The pathogenesis of hemorrhage induced by 3 purified components of C. atrox venom was studied at the light microscopic [LM] and EM levels. Crude venom was fractionated by anion exchange and gel filtration in 4 steps. .beta.-Alanine acetate disk gel electrophoresis was used to demonstrate electrophoretic homogeneity. White mice were injected i.m. with 0.1 ml of a sublethal dose of hemorrhagic toxin. Gross examination revealed extensive hemorrhage 5 min after the injection of hemorrhagic toxins a and e; the same amount of hemorrhage was not present until 3 h after the injection of hemorrhagic toxin b. LM examination of muscle after injection of the toxins revealed areas of extensive hemorrhage in which very few intact capillaries could be found and adjacent areas of slight hemorrhage in which capillaries were in various stages of degeneration. Necrosis of muscle cells was evident in tissue injected with hemorrhagic toxin b. EM examination showed that capillaries from toxin-injected muscle were in various stages of degeneration. Endothelial cells became very thin and broke down into vesicles prior to complete rupture. Gaps were formed within the cells while intercellular junctions remained intact. Plasma and erythrocytes leaked through these gaps and were observed in the endomysium. Many gaps were plugged with platelet aggregations. Collagen and the basal lamina associated with capillaries were usually disorganized or absent. The experimental injection of 3 purified hemorrhagic toxins induced hemorrhage by the same mechanism as does the crude venom, i.e., by rupture. One of the toxins, hemorrhagic toxin b, causes myonecrosis.