Early Embryonic Cortisol Exposure of Zebrafish Embryos Alters Morphology and Tissue Cortisol Concentration

Abstract

Cortisol is a stress hormone essential for human fetal development of the brain, lungs, and kidneys. Increased prenatal cortisol exposure due to maternal stress can alter fetal neurodevelopment. We investigated how exposure to cortisol affects early embryonic development in zebrafish. Embryos were treated with different concentrations of cortisol (10-100µM) beginning at 3 hours postfertilization (hpf). Fish were imaged at 72 hpf on an EVOS m5000 Imaging System and subsequently screened for six phenotypes: survival, pericardial edema, yolk sac edema, craniofacial development, body length, and body axis curvature. Cortisol levels within fish tissue were assayed with a Cortisol ELISA kit to serve as another indicator of the effects of cortisol exposure on embryonic development. Initial microscopy results suggest dose-dependent changes in morphological development of zebrafish embryos exposed to cortisol, with no change in survival rate. Additionally, initial results from the ELISA assay also show a dose-dependent change in the cortisol concentration within the tissue of zebrafish exposed to cortisol. Results from these experiments can help define the impact of embryonic cortisol exposure and contribute toward understanding prenatal development under maternal stress in humans.