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Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
Maternal dexamethasone and EEG hyperactivity in preterm fetal sheep
Joanne O Davidson1, Josine S L T Quaedackers, Sherly A George
1Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand.
The Journal of Physiology
|June 8, 2011
Summary
Maternal dexamethasone (DEX) exposure in fetal sheep caused transient brain hyperactivity and seizures, followed by altered sleep patterns. These changes may explain improved neonatal outcomes despite transient fetal brain effects.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Maternal corticosteroid use, like dexamethasone (DEX), improves neonatal outcomes.
- However, the precise impact of DEX on the developing fetal brain remains incompletely understood.
Purpose of the Study:
- To investigate the effects of maternal DEX administration on fetal brain electroencephalogram (EEG) activity in preterm sheep.
Main Methods:
- Preterm fetal sheep at 103 days gestation received two intramuscular injections of DEX or saline vehicle 24 hours apart.
- Fetal EEG activity was continuously recorded before and after the injections.
Main Results:
- DEX induced a transient increase in total EEG power with a shift towards lower frequencies (delta) and reduced higher frequencies (theta, alpha, beta).
- Epileptiform activity, suggestive of seizures, emerged after DEX administration.
- Sustained increases in alpha activity and alterations in sleep architecture (reduced interburst intervals) were observed post-injection, without evidence of neural injury.
Conclusions:
- Maternal DEX exposure causes significant, evolving changes in fetal cortical EEG, including hyperactivity and seizure-like activity.
- These EEG alterations are followed by changes indicative of accelerated maturation of fetal sleep architecture.
- The observed effects on fetal brain activity may underlie the beneficial neonatal outcomes associated with antenatal corticosteroid treatment.
