Effect of various Viperidae and Crotalidae snake venoms on endothelial cells in vitro

The effect of various crotalid and viperid venoms at 10, 50 and 100 micrograms/ml was examined on bovine and murine endothelial cells in vitro. The venoms caused the cells to lose their processes, leading to the appearance of spaces which were gradually enlarged between clusters of cells. The cells became round and finally detached from the substrate. This effect was more pronounced on bovine normal cells than on murine transformed cells. Most of the venoms did not affect the viability of the cells even after 24 hr of incubation, as determined by the trypan blue dye exclusion procedure. Moreover, after the cells were washed from the venoms and transferred into fresh medium, they regained their original morphology after spreading on the substrate and they then proliferated normally. This reversible effect shows that most of the crotalid and viperid venoms examined were not directly cytotoxic to the endothelial cells at the concentrations tested.