The toadstool death cap (Amanita phalloides) and its subspecies, destroying angel (A. virosa) and death angel (A. verna) are responsible for nearly 95% of all fatal
mushroom poisonings. High mortality rate in A. phalloides intoxications is principally a result of the
acute liver failure following significant hepatocyte damage due to hepatocellular uptake of
amanitins, the major toxins of this mushroom. This study evaluated early morphological and functional alterations in hepatocytes exposed to different concentrations of
alpha-amanitin (alpha-AMA). All experiments were performed on cultured canine hepatocytes since intoxicated with A. phalloides dogs have
clinical course and pathological findings similar to those seen in humans. The overall functional integrity and viability of cultured hepatocytes were assessed using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide] assay and by measurements of
lactate dehydrogenase (LDH), total
protein, and
urea levels. Our results showed that the course of alpha-AMA toxicity in cultured dog hepatocytes is divided into two phases. The first phase comprises functional cell impairments expressed by significant increase of LDH activity and inhibition of
protein and
urea synthesis when compared with the control group. This is followed by discrete changes in hepatocyte ultrastructure, including marginalization and condensation of nuclear
chromatin, as well as formation of the foamlike cytoplasm. The second stage is lethal and is characterized by ongoing
necrosis, and/or apoptosis. This may be related to dose of toxin and time of exposure.