Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas.
Birth Defects Res. 2019 Jul 15;111(12):700-713. doi: 10.1002/bdr2.1477. Epub 2019 Feb 21.
A cardinal feature of prenatal ethanol exposure is CNS damage, resulting in a continuum of neurological and behavioral impairments that are described by the term fetal alcohol spectrum disorders (FASD). FASDs are variable and depend on several factors, including the amount, timing, and duration of prenatal ethanol exposure. To enhance interventions for CNS dysfunction, it is necessary to identify ethanol-sensitive neuronal populations and expand the understanding of factors that modify ethanol teratogenesis.
To investigate the susceptibility of different neuronal subtypes, we exposed transgenic zebrafish (Danio rerio) to several ethanol concentrations (0.25, 0.5, 1.0, 1.5, or 2.0%), at different hours post fertilization (hpf; 0, 6, or 24 hpf), for various durations (0-24, 0-48, 4-24, 6-24, 6-48,or 24-48 hpf). Following exposure, embryo survival rates were determined, and CNS neurogenesis, differentiation, and patterning were assessed.
Embryo survival rates decrease as ethanol concentrations increase and drastically decline when exposed from 0-24 hpf compared to 4-24 hpf. Abnormal tangential migration of facial motor neurons is observed in isl1:gfp embryos exposed to ethanol concentrations as low as 0.25%, and the formation of IVth ventricle heterotopias are revealed by embryos exposed to ≥1.0% ethanol. Whereas, expression of olig2:dsred and ptf1a:gfp in the cerebellum and spinal cord are largely unaffected. While levels of etv4 mRNA are overtly resistant to ethanol, we observe significant reductions in ptch2 mRNA levels.
These data show differentially sensitive CNS neuron subpopulations with susceptibility to low levels of ethanol. In addition, these data reveal the formation of ethanol-induced hindbrain heterotopias.
产前乙醇暴露的一个主要特征是中枢神经系统损伤，导致一系列神经和行为损伤，这些损伤被称为胎儿酒精谱系障碍（FASD）。FASD 是可变的，取决于几个因素，包括产前乙醇暴露的量、时间和持续时间。为了增强对中枢神经系统功能障碍的干预，有必要确定对乙醇敏感的神经元群体，并扩大对改变乙醇致畸作用的因素的理解。
为了研究不同神经元亚型的易感性，我们将转基因斑马鱼（Danio rerio）暴露于几种乙醇浓度（0.25、0.5、1.0、1.5 或 2.0%），在受精后不同时间点（0、6 或 24 hpf），不同时间（0-24、0-48、4-24、6-24、6-48 或 24-48 hpf）。暴露后，确定胚胎存活率，并评估中枢神经系统神经发生、分化和模式形成。
胚胎存活率随着乙醇浓度的增加而降低，并且在 0-24 hpf 暴露时与 4-24 hpf 相比急剧下降。在 0.25%的乙醇浓度下，isl1:gfp 胚胎中观察到面部运动神经元的异常切线迁移，而在≥1.0%的乙醇暴露下，IV 脑室异位发生。然而，小脑和脊髓中的 olig2:dsred 和 ptf1a:gfp 表达基本不受影响。虽然 etv4 mRNA 的水平对乙醇明显有抗性，但我们观察到 ptch2 mRNA 水平显著降低。
这些数据显示出对低水平乙醇敏感的中枢神经系统神经元亚群存在差异。此外，这些数据揭示了乙醇诱导的后脑畸形的形成。
