Histopathological changes in WEHI-3B leukemia cells following intoxication by cytotoxin P₄ from Naja nigricollis nigricollis venom

The histopathological changes in WEHI-3B leukemia cells were followed by light and electromicroscopy at different time intervals following exposure to cytotoxin P₄ from Naja nigricollis nigricollis venom. At 1 hr after exposure to the toxin (2.5 × 10^-7 M) deformation was detected, primarily in the mitochondria, followed by vacuolization in the cytoplasm and an increase in lysosome number at 2 hr post-intoxication. Thereafter, the endoplasmic reticulum assumed a microsomal-like appearance, the plasma membrane was disrupted and, finally, the cells released their content to the culture medium. It is postulated that cytotoxin P₄ may affect mitochondria either indirectly, by stimulating intracellular processes after binding to the cell mebrane, or directly by interaction with the mitochondria after penetrating into the cell.