Effects of prolonged ethanol exposure on the glial fibrillary acidic protein-containing intermediate filaments of astrocytes in primary culture: a quantitative immunofluorescence and immunogold electron microscopic study.

Abstract

We investigated the effects of ethanol exposure on the shape of the cell and the morphology of intermediate filaments (IF) of cortical astrocytes in primary culture. The content and distribution of glial fibrillary acidic protein (GFAP), the major component of glial IF, was assessed using an anti-GFAP monoclonal antibody and fluorescence scanning densitometry together with quantitative pre- and post-embedding immunogold electron microscopy. The astrocytes were from 21-day-old fetuses obtained from both control and chronic alcoholic rats and were cultured for 28 days in the absence or presence of ethanol (25 mM). The main findings were: (a) ethanol-exposed astrocytes failed to develop processes or to acquire a filamentous IF distribution pattern; (b) these cells showed less GFAP than astrocytes without alcohol; (c) ethanol interfered with the reorganization of the anti-GFAP binding sites from clustered to random; and (d) astrocytes from alcohol-exposed fetuses cultured in the absence of ethanol also showed these alterations, suggesting initial damage to astrocyte precursor cells. Since the glial filaments play a crucial role in creating a scaffolding that guides neuronal migration, the effect of ethanol on astrocyte IF may possibly be correlated with the mechanisms underlying mental retardation and motor dysfunction which are characteristics of fetal alcohol syndrome.

Ethanol Exposure Affects Glial Fibrillary Acidic Protein Gene Expression and Transcription During Rat Brain Development

“…Cells obtained from PEE fetuses showed, as previously described (Renau-Piqueras et al, 1989;Sáez et al, 1991), alterations of intermediate filament organization pattern and delayed morphological astrocyte differentiation.…”

“…Control and prenatally ethanol-exposed (PEE) primary cultures of astrocytes from 21-day-old fetuses were prepared from brain hemispheres as described by Renau-Piqueras et al (1989). In brief, fetuses were obtained under sterile conditions from both control and chronic alcoholic rats.…”

Apolipoprotein D mediates autocrine protection of astrocytes and controls their reactivity level, contributing to the functional maintenance of paraquat-challenged dopaminergic systems

“…5D lower panels). Since the intermediary filament cytoskeleton is a sensitive sensor of toxic effects upon astrocytes (Pekny and Nilsson, 2005;Renau-Piqueras et al, 1989), this cellular distribution of GFAP might be the result of a basal stress produced by the lack of ApoD.…”

Glial and Neuroimmune Mechanisms as Critical Modulators of Drug Use and Abuse

“…Functional alterations in related circuits, including the central amygdala, frontal cortex, NAc, and bed nucleus of the stria terminalis (BNST) have been vigorously examined, and several molecular mechanisms have been implicated in the transition from acute to chronic alcohol consumption, including corticotropin-releasing factor (CRF), neuropeptide Y (NPY), and endogenous opioids (Mitchell et Although alcohol-induced effects on glia have not been as extensively characterized as its effects on neurons, accumulating evidence suggests that both microglia and astrocytes are impacted by acute and chronic alcohol. Early in vitro work with astrocyte progenitors cultured from fetal rat brains found that acute alcohol resulted in reduced GFAP expression in addition to stunted astrocyte cell proliferation (Guerri et al, 1990;Renau-Piqueras et al, 1989). In vivo, rats given free access to alcohol show increased activation of astrocytes (measured by GFAP) in discrete subregions of the hippocampus following shorter exposure periods (4-12 weeks), but decreased astrocyte activation was observed following extended drug access (36 weeks) (Franke, 1995).…”