Effect of diazinon, an organophosphate pesticide, on signal transduction and death induction in mononuclear cells of Nile tilapia fish (Oreochromis niloticus).

Diazinon (DZN) is an organophosphate pesticide characterized by inhibiting the enzyme acetylcholinesterase (AChE) (E.C. 3.1.1.7), affecting the nervous system. There is currently enough evidence proving this pesticide also affects the immune response; however, the immunotoxicity mechanisms through which these substances exerts toxic effects remain unclear. For that reason, this work evaluated the effect of diazinon on the intracellular calcium flux, ERK1/2 phosphorylation (pERK1/2), apoptosis, senescence, and mitochondrial membrane potential (ΔΨm) in spleen mononuclear cells (SMNC) of Nile tilapia, a teleost fish of commercial and ecological relevance. The results obtained indicate that diazinon causes significant damage in all evaluated parameters, which play an essential role in intracytoplasmic signaling of immune cells, suggesting these signal pathways could be related with the immunotoxicity mechanism of these type of pesticides. • DZN provokes alteration in intracytoplasmatic signals. • DZN increases the flow of intracellular Ca2+ and ERK1/2 phosphorylation in leukocytes of Nile tilapia. • DZN causes loss of ΔΨm and induces senescence and apoptosis in fish leukocytes. [ABSTRACT FROM AUTHOR]