Investigation of Cell Type-Specific Loss in the Nucleus Reuniens of the Midline Thalamus following Single-Day Alcohol Exposure in a Rodent Model of FASD
Date
2023-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Fetal Alcohol Spectrum Disorders (FASDs) is an umbrella term used to
describe multiple developmental disorders stemming from the prenatal alcohol
exposure that are manifested by deficits in growth development, cognitive
impairments, and physical abnormalities. 2-5% of live births in the US are affected by
FASD and result in lower brain volume, brain anomalies, and behavioral deficits
including impaired executive function. Executive function (EF) defines a set of
cognitive controls that aid in the formation of goal-directed movements and regulating
self-control; EF has been shown to relate to medial prefrontal cortex (mPFC) and
hippocampus (HPC) activity. An intermediary structure, the nucleus reuniens (Re) of
the midline thalamus, facilitates communication between the mPFC and HPC and is
known to be damaged by prenatal alcohol exposure. A damaged Re is known to
produce deficits in EF due to inefficient communication in the mPFC-Re-HPC circuit.
This study employed a rodent model of third-trimester single-day binge
alcohol exposure (AE) to evaluate neuroanatomical effects of neonatal alcohol
exposure. Specifically, we examined moderate (3g/kg/day), and high (5/25g/kg/day)
doses of ethanol compared to a sham-intubated control group. In conjunction with
histological immunofluorescence staining, this study measured the numbers of specific
cell populations in Re to assess levels of cell loss at 12hrs after AE. Specifically, we
estimated the total number of neurons and oligodendrocytes in Re by labelling these
cells with specific antibody markers NeuN (neuronal marker) and CC1 (marker for
mature oligodendrocytes).
No significant effect of postnatal treatment was found on neuron and
oligodendrocyte populations in Re which indicates that cell loss might occur later than
12 hours following AE, as found in studies examining apoptotic-cell expression at 5
and 24 hours (Phanithi, et al., 2000). Additionally, no significant effect of alcohol
exposure on reuniens volume was found, indicating that reuniens volume was not
compromised within 12 hours of AE. This study aids in our understanding of FASD
and adds to the general portrait of the effects of ethanol on the brain and Re