Influence of chronic alcohol treatment on the GFAP-immunoreactivity in astrocytes of the hippocampus in rats.

The influence of long term application of 5% (v/v) ethanol over a period of 36 weeks and 10% (v/v) ethanol over a period of 4,12 and 36 weeks to Wistar rats was investigated. The qualitative alterations of astrocytes and quantitative changes of glial fibrillary acidic protein-immunoreactivity (GFAP-IR) in selected regions of the dorsal hippocampus were examined, using anti-GFAP and the avidin-biotin immunoperoxidase technique. After prolonged (36 weeks) consumption of 5% (v/v) ethanol insignificant alterations were observed. The administration of 10% (v/v) ethanol over 4 and 12 weeks led to an increase of the total GFAP-IR in the examined brain regions. Hypertrophy of the cell bodies and cytoplasmic processes were seen. After 36 weeks decreased total GFAP-IR was measured in all examined brain regions. Cell bodies and fibrillary processes stained less heavily, the number and length of the fibrillary processes decreased and the number of astrocytes in certain hippocampal regions (e.g. in stratum moleculare of the dentate gyrus) appeared reduced. The results show that exposition to ethanol led to the appearance of different astrocytic phenotypes, depending on the concentration and duration of ethanol application, on the age of animals and on hippocampal regions. It is suggested that GFAP can be used as a specific marker for ethanol-induced alterations of astrocytes.