A selective loss of small‐diameter myelinated optic nerve axons in rats prenatally exposed to ethanol

Abstract

ABSTRACT  Pregnant rats were fed an ethanol‐containing liquid diet between gestational days 10 and 21. The optic nerves of their litters at 49 days of age were examined using quantitative stereological procedures. Cross‐sectional areas of the optic nerve in ethanol‐exposed rats were significantly smaller than those in controls. This was reflected in the reduced number of myelinated fibers, but not of non‐myelinated fibers. The size distribution histogram indicated a decreased number of small axonal‐diameter myelinated fibers in ethanol‐exposed rats. The results suggested optic nerve hypoplasia hi ethanol‐exposed rats characterized by a selective loss of small‐diameter myelinated fibers.