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Induction of apoptosis by mercury compounds depends on maturation and is not associated with microglial activation.
Journal article

Induction of apoptosis by mercury compounds depends on maturation and is not associated with microglial activation.

  • Monnet-Tschudi F Institute of Physiology, University of Lausanne, Switzerland. Floriane.Monnet@iphysiol.unil.ch
  • 1998-08-11
Published in:
  • Journal of neuroscience research. - 1998
Animals
Anti-Infective Agents, Local
Apoptosis
Biotin
Cell Differentiation
Cell Nucleus
Cells, Cultured
DNA Fragmentation
Deoxyuracil Nucleotides
Dose-Response Relationship, Drug
Fetus
Mercuric Chloride
Methylmercury Compounds
Microglia
Neurons
Rats
Staining and Labeling
English The earliest sign of neurotoxicity observed after exposure of three-dimensional brain cell cultures to low concentrations of mercury compounds is a microglial reaction. We hypothesized that an induction of apoptosis by mercury compounds could be an activating signal of the microglial reaction. Aggregating brain cell cultures of fetal rat telencephalon were treated for 10 days with either mercury chloride or monomethylmercury chloride at noncytotoxic concentrations during two developmental periods: from day 5 to 15, corresponding to an immature stage, and from day 25 to 35 corresponding to a mature stage. Apoptosis was evaluated by the TUNEL technique. It was found that both mercury compounds caused a significant increase in the number of apoptotic cells, but exclusively in immature cultures exhibiting also spontaneous apoptosis. Double staining by the TUNEL technique combined with either neuronal or astroglial markers revealed that the proportion of cells undergoing apoptosis was highest for astrocytes. Furthermore neither an association nor a colocalization was found between apoptotic cells and microglial cells. In conclusion, it appears that the induction of apoptosis by mercury compounds in immature cells is only an acceleration of a spontaneously occurring process, and that it is not a directly related to the early microglial reaction.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.ch/global/documents/93463
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