Aflatoxin B1 Cytotoxicity in Neurons in Culture

Abstract

Aflatoxin B1 (AFB1), a metabolite produced by Aspergillus flavus and Aspergillus parasiticus, is mainly known for its strong hepatotoxic and hepatocarcinogenic actions. Acute and reversible effects due to exposure to aflatoxin and the presence of aflatoxins in various human tissues and organs have also been reported. In particular, aflatoxin M1 (a metabolite of AFB1) has been identified in human brain tissue, and a syndrome characterised by encephalopathy has been observed in humans poisoned by AFB1. As a first approach to the study of the neurotoxicity of AFB1, we used the human neuronal cell lines, SKNMC and SKNSH. The data reported show clearly that AFB1 is capable of interacting directly with neuronal cells and causing a decrease in cell number following the addition of toxin to the culture. Decrease in cell survival is dependent on the toxin concentration, on time of exposure, and on cell density. The cytotoxic response of these cells has been compared to the effects of AFB1 on hepatoma cells and spinal cord motor neurons. Postmitotic neurons are also susceptible to AFB1 toxicity, although to a lower extent than proliferating cells. A non-proliferating state thus appears to lower, but not destroy, neuron sensitivity to the toxin.