A Stereological Analysis of the Effect of Early Postnatal Ethanol Exposure on Neuronal Numbers in Rat Dentate Gyrus

Abstract

Maternal ethanol ingestion during pregnancy can cause fetal alcohol syndrome (FAS) in their offspring. Among the symptoms of FAS, damage to the central nervous system has emerged as one of the most serious problems. We have previously shown that a relatively high dose of ethanol exposure during early postnatal life can cause alterations in spatial learning ability. This ability is controlled, at least in part, by the hippocampal formation. The purpose of the present study was to determine whether exposure of rat pups to ethanol during early postnatal life had effects on the total number of the dentate gyrus neurons. Wistar rats were exposed to a relatively high daily dose of ethanol between postnatal days 10 to 15. Ethanol exposure was achieved by placing rat pups in a chamber containing ethanol vapour for 3 hours a day. The blood ethanol concentration was found to be about 430 mg/dL at the end of the exposure period. Groups of ethanol treated (ET), separation controls (SC) and mother reared controls (MRC) were anaesthetised and killed at 16-days-of-age by perfusion with phosphate-buffered 2.5% glutaraldehyde. The Cavalieri principle was used to determine the volume of subdivisions of the dentate gyrus, and the physical disector method was used to estimate the numerical densities of neurons within each subdivision. The total number of neurons was calculated by multiplying estimates of the numerical density with the volume. There was, on average, about 421,000 granule cells in all three treatment groups. In the hilus region, ET rats had about 27,000 neuronal cells. This value was significantly smaller than the average of 38,000 such neurons estimated to be present in both MRC and SC animals. It is concluded that neurons in the hilus region of the dentate gyrus may be particularly vulnerable to the effects of a high dose of ethanol exposure during PND 10-15. It is likely that this deficit was due to neuronal death induced by some mechanisms related to the ethanol exposure

Chronic prenatal exposure to the 900 megahertz electromagnetic field induces pyramidal cell loss in the hippocampus of newborn rats

“…It is commonly known that hippocampus involves in the control of some behavioral and cognitive functions, including learning and memory (Lemaire, et al, 2000;Miki, et al, 2000;Eyre, et al, 2003). It has two main cell types -pyramidal and granule cells.…”

“…An understanding of the effect of prenatal exposure to EMF on the total neuron number of the hippocampus is important for understanding the process of CNS maturation as well as animal behaviors in postnatal life. It is commonly known that hippocampus involves in the control of some behavioral and cognitive functions, including learning and memory (Lemaire, et al, 2000;Miki, et al, 2000;Eyre, et al, 2003). It has two main cell types pyramidal and granule cells.…”

The Effects of Progesterone on Hypoxic Ischemic Injuries in the Cornu Ammonis (CA) Region of the Hippocampus of Neonatal Rats

“…The tissue blocks were cut horizontally in serial sections at 4 µm thickness using rotator microtome (Leica, UK). The first section that cut through the hippocampal tissue was numbered as the first section and all subsequent sections were numbered sequentially (Miki et al 2000a(Miki et al , 2000b. A number between 1 and 80 was randomly selected (Fig.…”