"In vitro" effects of methyl-mercury on the nervous system: a neurotoxicologic study

Many of the currently prevailing toxicologic problems are due to the use of organic mercurial compounds in pesticides and fungicides. During recent years, environmental pollution has originated from the incorrect use of these organometals. Methyl-mercury (Me-Hg) is absorbed quickly from the gastrointestinal tract and is distributed to most tissues. The most important effect of Me-Hg is on the nervous tissue and is more relevant in the fetal brain. We were interested in assessing the neurotoxic effects of Me-Hg on the central and peripheral nervous system. Neuronal cells cultures from 14-day-old fetal Wistar rats and ciliary ganglion cells cultures from 8-day-old chick embryos were used. Various Me-Hg concentrations (10(-3) M to 10(-8) M) were added to these cultures after 36 hr to study the morphologic changes. At 10(-3) M and 10(-4) M concentrations, cellular degeneration and death in the central nervous system (CNS) were noted. At 10(-5) M concentrations, axonal and nerve fibers degeneration, loss of synapsis, and inhibition in the cellular development in CNS were seen; regroupment and destruction in the peripheral nervous system (PNS) was noted. Finally, at 10(-6) M and 10(-7) M concentrations, there were hardly any modifications in the CNS, whereas only the nervous processes were affected in the PNS.