Investigation of developmental defects of zebrafish embryos caused by alcohol consumption using optical coherence microscopy

Alcohol consumption during pregnancy is highly teratogenic, leading to a broad range of irreversible side effects. Zebrafish are an ideal model for studying early embryogenesis because they produce hundreds of embryos that develop externally that are synchronized at the same developmental stage, and the transparency of the embryos enables easy imaging with a variety of optical techniques. Ethanol exposure from 6 to 24 hours post-fertilization consistently induces FASD-like defects in zebrafish, including craniofacial, cardiac, and neural anomalies. In this work, we simulated chronic ethanol exposure during early pregnancy stages, which is most often when mothers may unknowingly consume alcohol. Fertilized zebrafish embryos were exposed to varying ethanol concentrations (1%, 1.5%, and 2%) from 6 to 24 hours postfertilization. Optical coherence microscopy (OCM) is a high resolution and depth-resolved imaging modality and imaged the brain and eye of the zebrafish embryos. At 2% ethanol concentration, zebrafish embryos exhibited a notable reduction in eye size and change in heart rate. The developmental impact of early ethanol exposure on zebrafish varied based on the embryo age and the exposure pattern. Research into the mechanisms of alcohol's teratogenic effects predominantly employs translational animal models due to ethical and practical limitations in human studies, and OCM shows great promise for high-resolution and high-throughput phenotyping of zebrafish embryos in vivo without the need for exogeneous contrast agents or transgenic models.