Timed Prenatal Ethanol Exposure and Postnatal Cortical Oligodendrocyte and White Matter Changes in Young Wistar Rats

Abstract

BACKGROUND: The study evaluated postnatal white matter changes following prenatal ethanol exposure in the first, second and third trimesters in Wistar rats sacrificed at the third and sixth postnatal week. This was with a view to providing information on the state of oligodendrocyte and subcortical white matter in prenatal alcohol exposure.
METHODS: Twenty (20) mature female Wistar rats were time-mated and randomly divided into 4 groups (n=5). Group 1 (control) received distilled water (2 mL/kg), Groups 2, 3 and 4 were administered 2.5 mL/kg of 20% ethanol orally on the 4th, 11th and 18th days of gestation respectively. All rats were allowed to litter and pups were weighed weekly. The brain was harvested at 3 and 6 postnatal weeks and fixed in 10% neutral buffered formalin. One mm thick coronal brain slice was at the optic chiasma plane were processed. 
Morphology and density of oligodendrocytes was studied using Haematoxylin and Eosin stain, while Luxol Fast Blue (LFB) stain was used for white matter morphometry. Data was analyzed using Student t-test. P value < 0.05 was considered statistically significant.
RESULTS: At the third week of postnatal life there was significant reduction in the subcortical white matter thickness which became reversible at the sixth postnatal week while there was no significant difference in the cortical oligodendrocyte density at both the third and sixth postnatal week, however regional comparison showed some differences at the two time lines.
CONCLUSION: The study concluded that prenatal ethanol exposure causes white matter reduction at the third week of postnatal life in Wistar rats with reversal at the sixth week.