Faculty Collaboration Database

Regional Patterns of Alcohol-Induced Neuronal Loss Depend on Genetics: Implications for Fetal Alcohol Spectrum Disorder. Alcohol Clin Exp Res 2018 Sep;42(9):1627-1639

Date

06/30/2018

Pubmed ID

29957842

Pubmed Central ID

PMC6445660

DOI

10.1111/acer.13824

Scopus ID

2-s2.0-85050468586 (requires institutional sign-in at Scopus site)   5 Citations

Abstract

BACKGROUND: Alcohol exposure during pregnancy can kill developing neurons and lead to fetal alcohol spectrum disorder (FASD). However, affected individuals differ in their regional patterns of alcohol-induced neuropathology. Because neuroprotective genes are expressed in spatially selective ways, their mutation could increase the vulnerability of some brain regions, but not others, to alcohol teratogenicity. The objective of this study was to determine whether a null mutation of neuronal nitric oxide synthase (nNOS) can increase the vulnerability of some brain regions, but not others, to alcohol-induced neuronal losses.

METHODS: Immunohistochemistry identified brain regions in which nNOS is present or absent throughout postnatal development. Mice genetically deficient for nNOS (nNOS^-/- ) and wild-type controls received alcohol (0.0, 2.2, or 4.4 mg/g/d) over postnatal days (PD) 4 to 9. Mice were sacrificed in adulthood (~PD 115), and surviving neurons in the olfactory bulb granular layer and brain stem facial nucleus were quantified stereologically.

RESULTS: nNOS was expressed throughout postnatal development in olfactory bulb granule cells but was never expressed in the facial nucleus. In wild-type mice, alcohol reduced neuronal survival to similar degrees in both cell populations. However, null mutation of nNOS more than doubled alcohol-induced cell death in the olfactory bulb granule cells, while the mutation had no effect on the facial nucleus neurons. As a result, in nNOS^-/- mice, alcohol caused substantially more cell loss in the olfactory bulb than in the facial nucleus.

CONCLUSIONS: Mutation of the nNOS gene substantially increases vulnerability to alcohol-induced cell loss in a brain region where the gene is expressed (olfactory bulb), but not in a separate brain region, where the gene is not expressed (facial nucleus). Thus, differences in genotype may explain why some individuals are vulnerable to FASD, while others are not, and may determine the specific patterns of neuropathology in children with FASD.

Author List

Todd D, Bonthius DJ Jr, Sabalo LM, Roghair J, Karacay B, Bousquet SL, Bonthius DJ

MESH terms used to index this publication - Major topics in bold

Alcohol Drinking
Animals
Animals, Newborn
Ethanol
Female
Fetal Alcohol Spectrum Disorders
Male
Mice
Mice, 129 Strain
Mice, Inbred C57BL
Mice, Knockout
Neurons
Nitric Oxide Synthase Type I
Olfactory Bulb
Pregnancy
Random Allocation