Pregnant female mice were divided on day 12 post coitum into a
control and an experimental group. The
experimental group was given a single intraperitoneal dose of 0.015 ml/g
body weight of 25% solution of
alcohol in distilled water while the control group was exposed to a
similar weight related dose of normal
saline. The optic nerves were isolated from the offspring of both
control and experimental groups at wk 2,
3 and 5 (i.e. during the juvenile period of postnatal development)
and analysed by light and electron
microscopy. Although in both groups the optic nerve grew in size
rapidly during the period studied, the rate
of growth in the experimental groups lagged behind that of the controls.
The difference was initially
significant but tailed off, so that by wk 5 it was no longer significant.
The time of initial onset and
progression of myelinogenesis in the optic nerve of alcohol exposed
mice also lagged behind that of controls.
In both groups the size distribution of the myelinated nerve fibres
in the optic nerve was unimodal with a
positive skewing for all ages. The spectrum of size distribution of the
nerve
fibres was, however, broader in
controls than in the corresponding experimental groups. With increasing
age the proportion of small and
medium size fibres was greater in the experimental group than in the
controls, while for the large diameter
fibres the reverse was observed. It is suggested that this study may shed
light
on the teratogenic effect of
‘binge’ drinking during pregnancy and that it is the critical
period when exposure occurs that is more
important than the duration of administration.