Aflatoxin B 1 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.