Mechanism involved in cell death induced by DEHP (Di-ethylhexyl phthalate) on primary brain cells from Zebrafish (Danio rerio)

Abstract

Human and ecological exposure to chemical contaminants continue to increase given anthropogenic activities and sources. Phthalates are among the most persistent toxic chemicals found in aquatic systems. Phthalates belong to a family of chemical compounds that are heavily used in global manufacturing, distinguished for being able to provide durability and elasticity to plastic products, with poor water solubility and low evaporation. In terms of health impact, these compounds have been shown to breach the placental barrier having effect on human development and neurodegeneration. The main purpose of our study has been to assess the neurotoxicity of phthalates implementing the zebrafish (Danio rerio) model to determine the cell death induction of DEHP on brain cells. For many years, the zebrafish embryonic model has been used to study vertebrate development. Our study, in contrast, used adult zebrafish to resemble mature species that can be continuously exposed to low concentrations of DEHP. To assess the neurotoxicity, brain tissue from zebrafish was extracted via dissection, and primary neural cells dissociated to obtain primary cell subcultures. The neural cells where subsequently exposed to DEHP (Di-ethylhexyl phthalate) at concentrations from 10µM to 100µM for 48 hours to observe cell growth inhibition (GI50). The results indicate neural cell death at a GI50 of 62.9 µM. Apoptosis induction, caspase activation, mitochondrial membrane damage as well as autophagy cell death were analyzed to identify DEHP cell death mechanism at the GI50 concentration. In conclusion, this study clearly demonstrated that DEHP can induce apoptosis cell death on zebrafish neural brain cells in culture through the activation of an intrinsic apoptotic pathways with caspases 3 and 7 activation as well as autophagic pathway and mitochondrial damage. The presence of phthalates as well as other chemical contaminants on aquatic environments needs to be earnestly controlled in order to reduce neurotoxicity to aquatic species as well as human.