Dose-dependent decrease in glial fibrillary acidic protein-immunoreactivity in rat cerebellum after lifelong ethanol consumption

The effects of aging and lifelong ethanol consumption on astrocytic morphol ogy and glial fibrillary acidic protein-immunoreactivity (GFAP-IR) in the c erebellar vermis obtained from ethanol-preferring Alko, Alcohol (AA) rats w ere analyzed by using computer-assisted image analysis. The ethanol-consumi ng animals (both male and female) were given ethanol(10%-12%, vol./vol.) as the only available fluid for 21 months (from age 3 to 24 months), whereas the young (3 months) and the old (24 months) controls received water. In th e male rats, but not in the female rats, an age-related decrease in GFAP-IR was found in folia II, VII, and X of the molecular layer, and in turn, an age-related increase was found in folium X of the granular layer, indicatin g opposite changes in GFAP-IR for male rats due to aging in adjacent brain regions. In the female rats, 21 months of daily average ethanol consumption of 6.6 g/kg resulted in decreased GFAP-IR in folium VII of the molecular l ayer, and the decrease in cerebellar GFAP-IR correlated with the average da ily ethanol intake (r = -.886, P=.019) when folia II, IV, VII, and X were a nalyzed together. No effect of ethanol on GFAP-IR was detected in the granu lar layer or in the central white matter of the female rats. There was no c hange in GFAP-IR in any of the three cerebellar layers of the male rats wit h average daily ethanol consumption of 3.2 g/kg. These results indicate tha t the Bergmann glial fibers are the GFAP-expressing structures of the cereb ellum most sensitive to moderate-to-heavy chronic ethanol exposure and that this effect is dose dependent. (C) 2001 Elsevier Science Inc. All rights r eserved.