Hostname: page-component-848d4c4894-8kt4b Total loading time: 0 Render date: 2024-07-04T22:35:37.457Z Has data issue: false hasContentIssue false

Exposure of rats to a high but not low dose of ethanol during early postnatal life increases the rate of loss of optic nerve axons and decreases the rate of myelination

Published online by Cambridge University Press:  23 November 2000

SIMON J. HARRIS
Affiliation:
Department of Anatomical Sciences, University of Queensland, St Lucia, Brisbane, Australia
PETER WILCE
Affiliation:
Department of Biochemistry, University of Queensland, St Lucia, Brisbane, Australia
KULDIP S. BEDI
Affiliation:
Department of Anatomical Sciences, University of Queensland, St Lucia, Brisbane, Australia
Get access

Abstract

Visual system abnormalities are commonly encountered in the fetal alcohol syndrome although the level of exposure at which they become manifest is uncertain. In this study we have examined the effects of either low (ETLD) or high dose (ETHD) ethanol, given between postnatal days 4–9, on the axons of the rat optic nerve. Rats were exposed to ethanol vapour in a special chamber for a period of 3 h per day during the treatment period. The blood alcohol concentration in the ETLD animals averaged ∼ 171 mg/dl and in the ETHD animals ∼ 430 mg/dl at the end of the treatment on any given day. Groups of 10 and 30-d-old mother-reared control (MRC), separation control (SC), ETLD and ETHD rats were anaesthetised with an intraperitoneal injection of ketamine and xylazine, and killed by intracardiac perfusion with phosphate-buffered glutaraldehyde. In the 10-d-old rat optic nerves there was a total of ∼ 145000–165000 axons in MRC, SC and ETLD animals. About 4% of these fibres were myelinated. The differences between these groups were not statistically significant. However, the 10-d-old ETHD animals had only about 75000 optic nerve axons (P < 0.05) of which about 2.8% were myelinated. By 30 d of age there was a total of between 75000–90000 optic nerve axons, irrespective of the group examined. The proportion of axons which were myelinated at this age was still significantly lower (P < 0.001) in the ETHD animals (∼ 77%) than in the other groups (about 98%). It is concluded that the normal stages of development and maturation of the rat optic nerve axons, as assessed in this study, can be severely compromised by exposure to a relatively high (but not low) dose of ethanol between postnatal d 4 and 9.

Type
Research Article
Copyright
© Anatomical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)