Disappearance of astrocytes and invasion of macrophages following crush injury of adult rodent optic nerves: Implications for regeneration
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Glial scar
Neuroglia
Crush injury
Exposure to a mixture of As, Pb and Cd induces apoptosis and morphological alterations in the cortical astrocytes of rat brain. The levels of the glial fibrillary acidic protein (GFAP) undergo a reduction. The GFAP exists in several isoforms, viz., α, β, κ, δ and ϵ. However, contribution of the isoforms towards astrocyte damage is not understood. We investigated the effect of the metal mixture (MM) on the expression profiles of mRNAs encoding the GFAP isoforms in astrocytes. The MM was administered in drinking water to developing rats till postnatal day (PD) 60. We observed a fall (10.20 ± 1.04%, 18.91 ± 2.12% and 30.26 ± 3.21% at PD24, PD45 and PD60 respectively) in GFAPα. This may have been compensated by a rise in β, κ, and ϵ. The GFAPδ remained unchanged. To determine the role of the GFAPα, we silenced its gene using SiRNA technology in the rat primary astrocytes. We observed a 23.73 ± 1.56% increase in the number of apoptotic cells. The cleaved PARP and Bax levels increased by 2.48 ± 0.14-fold and 3.73 ± 0.23-fold respectively, and the Bcl-2 and Bcl-xl decreased by 2.38 ± 0.08-fold and 1.76 ± 0.09-fold respectively. The change was comparable to the cells treated with MM. Moreover, silencing the GFAPα gene induced a reduction in the area (6.19 ± 0.18-folds), perimeter (12.65 ± 1.68-folds) and the number of processes (5.88 ± 1.5-folds) in the astrocytes, which closely matched the MM-treated ones. Taken together, these observations are the first to show that MM disturbs the composition of the GFAP isoforms, and a suppressed GFAPα promotes apoptosis in the matured rat astrocytes.
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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.
Immunogold labelling
GFAP stain
Neuroglia
Immunofluorescence
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Previous studies of human hepatic encephalopathy (HE) have shown decreased levels of glial fibrillary acidic protein (GFAP) in Alzheimer type II astrocytes. In view of the important role of ammonia in the pathogenesis of HE, we carried out immunocytochemical and enzyme-linked immunosorbent assay (ELISA) studies on the effect of ammonium chloride (10 mM) on GFAP content in primary astrocyte cultures. There was a 39% loss of GFAP after a four day treatment. There was no fall in total cell protein. Potential mechanisms for this apparent selective loss of GFAP are discussed.
GFAP stain
Ammonium chloride
Neuroglia
Pathogenesis
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AIM: To observe the activity and distribution of astrocytes and glial fibrillary acid protein(GFAP) after middle cerebral artery occlusion (MCAO). METHODS: The rat MCAO model was made by two-kidney, tow clip renovascular hypertensive rat stroke prone(RHRSP). Rats were killed and brain samples were collected at the end of 1,3,6 and 9 weeks after MCAO, respectively. The ultrastructure of astrocytes was determined at broder of infarct (A area); distant of infarct (B area) and opposite of hemisphere (C area) by electron microscope. The number and optical density of GFAP-positive cells were also observed. RESULTS: The astrocyte proliferation distributed in the whole brain after MCAO. The highest numbers of GFAP-positive cells were observed at A area, then B area. The lowest numbers of GFAP positive cells were found in C area. The time course of GFAP-positive cell change was that the highest number was observed at 1 week after MCAO, then decreased by time from 3, 6 weeks to 9 weeks. The optical density of GFAP-positive cells showed the same patterns. CONCLUSION: The correlation between astrocyte proliferation and tissue damage after MCAO can be estimated by GFAP expression. The astrocyte proliferation plays an important role in healing process after MCAO.
GFAP stain
Optical density
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In the rat hippocampus and cortex, the transcription of glial fibrillary acidic protein (GFAP), an astrocyte intermediate filament protein, is inhibited by glucocorticoids. The present study examined the regulation of GFAP expression by glucocorticoids in astrocytes in vitro. Corticosterone (CORT) increased GFAP messenger RNA, protein, and transcription rates in cultured primary neonatal astrocytes, responses opposite the GFAP responses to CORT in vivo. The direction of GFAP regulation by corticosterone in vitro is reversed by coculture with neurons or by extended culture for 3 months. The switch in the direction of GFAP regulation by CORT during prolonged culture is associated with a 3-fold increased prevalence of type II glucocorticoid receptor (GR). These findings were corroborated with a promoter construct that contained 1.9 kilobases of 5'-up-stream rat GFAP DNA with a luciferase reporter. Thus, the direction of GFAP transcription to CORT is subject to the postreplicative time in culture and to interactions with neurons, in which 5'-up-stream sequences contain sufficient information to mediate the switch in the direction of the response to CORT. This in vitro model may be used to analyze how interactions of astrocytes with neurons or other cell types influence the hormonal regulation of GFAP.
Corticosterone
GFAP stain
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Journal Article Transcriptional regulation of glial fibrillary acidic protein by corticosterone in rat astrocytes in vitro is influenced by the duration of time in culture and by astrocyte-neuron interactions Get access I Rozovsky, I Rozovsky 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar N J Laping, N J Laping 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar K Krohn, K Krohn 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar B Teter, B Teter 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar J P O'Callaghan, J P O'Callaghan 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar C E Finch C E Finch 1Andrus Gerontology Center, University of Southern California, Los Angeles 90089-0191, USA. Search for other works by this author on: Oxford Academic Google Scholar Endocrinology, Volume 136, Issue 5, 1 May 1995, Pages 2066–2073, https://doi.org/10.1210/endo.136.5.7720656 Published: 01 May 1995
Corticosterone
Neuroglia
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Objective To establish a culture method of rat cerebral cortical astrocyte for further research on astrocyte in vitro.Methods Cerebral cortex of postnatal 5 days of SD rats were used basing on McCarthy method.Unicell suspension were prepared and inoculated in culture flask.Changed the culture flask after 1 hour and substratum was replaced after 3 days.Passage was done when cells syncretized to monolayer.Glial fibrillary acidic protein of the specifical sign of astrocyte was monitored by indirect immunofluorescence after three times passage.The masccline cells of glial fibrillary acidic protein were affirmed to be astrocyte.Results All cerebral cortical astrocytes cells which were cultured in vitro underwent adherence,fibroblast removed,depuration and passage three times,the rate of masccline cells of glial fibrillary acidic protein was above 95%.Conclusion Culture of cerebral cortical astrocytes in vitro is successful and there is higher purity.The condition was provided for further research of astrocytes.
GFAP stain
Immunofluorescence
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GFAP stain
Neurotoxicity
Neuroglia
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GFAP stain
Cloning (programming)
Trypsinization
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The effect of dexamethasone on astrocyte differentiation was investigated in vitro, using cultures of normal and transformed astrocytes. The astrocyte-enriched proteins glutamine synthetase (GS) and glial fibrillary acidic (GFA) protein were used as markers of astrocyte differentiation. Ethanol, the vehicle for dexamethasone, decreases GS activity and increases GFA protein concentration in cultures of the established cell line U251MG and in the majority of cultures of transformed astrocytes derived from varying grades of astrocytoma, Ethanol has no effect on primary cultures of astrocytes derived from immature rat brain. Dexamethasone increases GS activity and decreases GFA protein con centration in cultures of U251MG and a grade IV astrocytoma-derived culture, in comparison with ethanol control. Our results show differential effects of two factors on cell-specific proteins in normal and transformed astrocytes.
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