Selective Vulnerability of Embryonic Cell Populations to Ethanol-Induced Apoptosis: Implications for Alcohol-Related Birth Defects and Neurodevelopmental Disorder

Authors

  • William C. Dunty Jr,,

    1. Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies (WCD, S-yC, DBD, KKS), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and the Reproductive Toxicology Division (RMZ), National Health Effects and Environmental Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina.
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  • Shao-yu Chen,

    1. Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies (WCD, S-yC, DBD, KKS), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and the Reproductive Toxicology Division (RMZ), National Health Effects and Environmental Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina.
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  • Robert M. Zucker,

    1. Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies (WCD, S-yC, DBD, KKS), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and the Reproductive Toxicology Division (RMZ), National Health Effects and Environmental Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina.
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  • Deborah B. Dehart,

    1. Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies (WCD, S-yC, DBD, KKS), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and the Reproductive Toxicology Division (RMZ), National Health Effects and Environmental Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina.
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  • Kathleen K. Sulik

    Corresponding author
    1. Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies (WCD, S-yC, DBD, KKS), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; and the Reproductive Toxicology Division (RMZ), National Health Effects and Environmental Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina.
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  • The information in this document has been funded in part by the US Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

    This work was supported by Grant AA11605 from the NIAAA and a Predoctoral Training Grant in Research on Drug Abuse DA-07244 from the National Institute on Drug Abuse.

Kathleen K. Sulik, PhD, Bowles Center for Alcohol Studies, CB #7178, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090; Fax: 919-966-5679; E-mail: mouse@med.unc.edu.

Abstract

Background: Ethanol-induced cell death has been characterized in very few stages of embryogenesis. This investigation comprehensively maps patterns of both programmed and ethanol-induced cell death in the central nervous system and craniofacial region at 0.5-day intervals from gestational day (GD) 6.5 to 11 in mice.

Methods: A teratogenic dosage of ethanol (2.9 g/kg) or vehicle was administered via two intraperitoneal injections to pregnant C57BL/6J mice at various stages of gestation. Cell death patterns were characterized using Nile blue sulfate vital staining and histological analysis of plastic sections. Confocal laser scanning microscopy of LysoTracker Red–stained specimens allowed for three-dimensional visualization of areas of apoptosis and precise sectional imaging of mouse embryos. Apoptosis was also documented using a TUNEL technique on histological sections.

Results: Normal programmed cell death in control embryos was noted in the prechordal plate region at GD 8, the neuroepithelium of the fourth ventricle and anterior neuropore at GD 9, and within the ganglia of cranial nerves V, VII–VIII, IX, and X at GD 10. Acute maternal ethanol administration 12 hr before examination resulted in a dramatic increase in apoptosis within sites of programmed cell death in the embryo. Moreover, ethanol-exposed specimens exhibited stage-dependent excessive cell death in other distinct cell populations, particularly within the developing central nervous system. Ethanol-induced apoptosis was notable as follows: GD 7.5-neuroectoderm; GD 8-neural plate and primitive streak; GD 9-alar plate and presumptive neural crest of the rostral hindbrain, especially at the mesencephalon/rhombencephalon junction; GD 9.5–10-branchial arches and rhombomeres; and GD 11-diencephalon, basal ganglia, pons, and developing cerebellum.

Conclusions: The results of this study revealed developmental stage-specific cell populations of the developing brain and craniofacial region that are vulnerable to ethanol-induced apoptosis and provide new insight relative to the genesis of alcohol-related birth defects.

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