Apoptosis, oxidative stress and genotoxicity in developing zebrafish after aluminium exposure

Aluminium is a non-essential metal and potentially toxic to organisms whose environmental concentration increases due to pollution. In our previous studies, the behavioral changes induced by aluminium were already shown on zebrafish, a model organism widely used for ecotoxicology screening. To examine in depth the knowledge about the toxicity mechanism induced by this metal, zebrafish embryos, at 6 hpf, have been exposed to 50, 100 and 200 µM of AlCl₃ for 72 h. Phenotypic alterations, apoptosis and oxidative stress responses have been assessed by evaluations of antioxidant defence and changes in metabolism at the end of treatment. The mRNA expression level of c-fos, appa and appb as marker genes of neural development and function were analyzed by qPCR for the highest used concentration. The data showed that aluminium significantly affected the development of zebrafish inducing morphological alterations and cell death. The oxidative state of larvae was altered, although the formation of reactive oxygen species and the levels of metallothioneins, and the activity of some antioxidant enzymes, decreased at the maximum concentration tested. In addition, at this concentration, the expression of the evaluated genes increased. The comprehensive information obtained gives a realistic snapshot of the aluminium toxicity and provides new information on the mechanism of action of this metal.