Elemental mapping inventory of the fish Liza aurata brain: a biomarker of metal pollution vulnerability

Abstract

The elemental distributions in optic tectum of brains of wild Liza aurata a teleost fish captured in polluted and reference coastal areas were assessed quantitatively by nuclear microscopy providing insights into brain vulnerability to metal pollution. Elemental maps enabled us to visualize optic tectum layers and identify cellular arrangements. Whereas Cl, K and Ca contents identify meninges, the Ca, Fe and Zn concentrations distinguish the underneath grey matter, white matter and inner cellular layers. Exposed animals showed significantly decreased P concentrations and increased contents of Cu, Zn and Ni in all brain structures. These changes highlight homeostasis modification, altered permeability of the blood–brain barrier and suggest risk for neurological toxicity. Our study initiated for the first time an inventory of physiological measures containing images and elemental compositions of brain regions of fish exposed to different environmental conditions. This will help defining total and local brain vulnerability to metals and pollution levels.