In vitro hemotoxic, α-neurotoxic and vasculotoxic effects of the Mexican black-tailed rattlesnake (Crotalus molossus nigrescens) venom.

The Mexican black-tailed rattlesnake Crotalus molossus nigrescens is distributed in the Mexican plateau. Its venom is known to cause hemolysis and presents fibrinogen coagulase, collagenase and fibrinolytic activities. These activities may be associated with hemostatic alterations, such as platelet aggregation, hemolysis and fibrinolysis, often described in ophidic accidents. However, the mechanisms of action of the C. m. nigrescens venom remain unclear. In this study we investigated the in vitro hemotoxic, neurotoxic, and vasculotoxic effects of the venom. We found that this venom produces two types of hemolytic responses, Oxyhemoglobin release and Methemoglobin formation. As a result of the cytotoxicity to endothelial cells produces morphological biphasic toxicity. The first step in this process is characterized by morphological changes, as well as the loss of cellular adhesion and reduction in thickness. The second phase is characterized by massive cellular aggregation and death. It also induced laminin, type IV collagen, perlecan and nidogen degradation. However, the venom did not modulate the muscular fetal and neuronal nicotinic acetylcholine receptors activity. Thus, we concluded that the C. m. nigrescens venom produced hemolysis and hemorrhages via degradation of the basement membrane components and endothelial cell cytotoxicity, but not by neurotoxicity at the receptor level in nicotinic acetylcholine receptors.