Embryonic ethanol exposure induces oxidative stress and inflammation in zebrafish model: A dose-dependent study

Alcohol, or ethanol, is a major contributor to detrimental diseases and comorbidities worldwide. Alcohol use during pregnancy intervenes the developing embryos leading to morphological changes, neurocognitive defects, and behavioral changes known as fetal alcohol spectrum disorder (FASD). Zebrafish have been used as a model to study FASD; however, the mechanism and the impact of ethanol on oxidative stress and inflammation in the zebrafish FASD model remain unexplored. Hence, we exposed zebrafish embryos to different concentrations of ethanol (0 %, 0.5 %, 1.0 %, 1.25 %, and 1.5 % ethanol (v/v)) at 4-96 hours post-fertilization (hpf) to study and characterize the ethanol concentration for the FASD model to induce oxidative stress and inflammation. Here, we studied the survival rate and developmental toxicity parameters at different time points and measured oxidative stress, reactive oxygen species (ROS) generation, apoptosis, and pro-inflammatory gene expression in zebrafish larvae. Our findings indicate that ethanol causes various developmental abnormalities, including decreased survival rate, spontaneous tail coiling, hatching rate, heart rate, and body length, associated with increased malformation. Further, ethanol exposure induced oxidative stress by increasing lipid peroxidation and nitric oxide production and decreasing glutathione levels. Subsequently, ethanol increased ROS generation, apoptosis, and pro-inflammatory gene (TNF-α and IL-1β) expression in ethanol exposed larvae. 1.25 % and 1.5 % ethanol had significant impacts on zebrafish larvae in all studied parameters. However, 1.5 % ethanol showed decreased survival rate and increased malformations. Overall, 1.25 % ethanol is the ideal concentration to study the oxidative stress and inflammation in the zebrafish FASD model.