Isolation of intermediate filaments from rat astrocytes in culture

Macroglial cells of the teleost central nervous system: a survey of the main types

Following our previous review of teleost microglia, we focus here on the morphological and histochemical features of the three principal macroglia types in the teleost central nervous system (ependymal cells, astrocyte-like cells/radial glia and oligodendrocytes). This review is concerned with recent literature and not only provides insights into the various individual aspects of the different types of macroglial cells plus a comparison with mammalian glia, but also indicates the several potentials that the neural tissue of teleosts exhibits in neurobiological research. Indeed, some areas of the teleost brain are particularly suitable in terms of the establishment of a "simple" but complete research model (i.e. the visual pathway complex and the supramedullary neuron cluster in puffer fish). The relationships between neurons and glial cells are considered in fish, with the aim of providing an integrated picture of the complex ways in which neurons and glia communicate and collaborate in normal and injured neural tissues. The recent setting up of successful protocols for fish glia and mixed neuron-glia cultures, together with the molecular facilities offered by the knowledge of some teleost genomes, should allow consistent input towards the achievement of this aim.

Purification of glial fibrillary acidic protein (GFAP) from normal bovine brain

Glial fibrillary acidic protein (GFAP) was purified from normal bovine brain by a modification of the procedure used to isolate vimentin in order to avoid contamination by other cytoskeletal components: vimentin, neurofilament triplet proteins, tubulin and actin. GFAP is thought to be separated from vimentin in the DE cellulose column chromatography step. The three other major proteins were also separable through ion exchange and gel filtration column chromatographies. A purified 49 kDa polypeptide was estimated to be GFAP from peptide mapping and subsequent immunoblotting analysis. We obtained 4.4 mg GFAP/1 g bovine brain white matter in less than 3 days. The polyclonal antibody raised against purified GFAP was able to detect 49 kDa GFAP by immunoblotting analysis. This isolation method is simpler and more rapid than previous methods.

Immunocytochemical characterization of the A15 A5 transplantable brain tumour model in vivo

A comparative immunocytochemical study was carried out on intracerebral and extracranial gliomas of the rat produced by intracerebral injection of low (10th) and high (40th) in vitro passages of neoplastic glial cells. The cells injected were a neoplastic astrocytic clone-A15 A5-derived from a mixed glioma induced transplacentally by N-ethyl-N-nitrosourea (ENU) in a BD-IX rat. An inverse relationship was seen between the expression of the astrocytic markers glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) at low and high passage: GFAP decreased with increasing passage while GS increased. The distribution of vimentin, the major cytoskeletal component of immature glia, was constant, irrespective of passage--a feature consistent with previous in vitro findings. The expression of laminin by both reactive and neoplastic astrocytes increased with increasing passage, while high magnification examination revealed the presence of the glycoprotein fibronectin on the cell-surfaces of A15 A5-derived tumour cells. Both neoplastic and reactive astrocytes expressed S-100 protein with a higher proportion of positive cells in extracranial tumours. Occasional cells, probably actively phagocytizing populations of reactive astrocytes and macrophages, were positive for alpha-1-antitrypsin. None of the neoplastic cells expressed the oligodendrocyte marker carbonic anhydrase II. This immunocytochemical study supports previous morphological findings in differences in differentiation between the cells of tumours produced by high and low passage cells.

Immunocytochemical demonstration of both carbonic anhydrase isoenzyme II and glial fibrillary acidic protein in some immature rat glial cells in primary culture

In glial cell cultures from newborn rat hemispheres we have demonstrated by immunocytochemistry the presence of carbonic anhydrase (CAII) and glial fibrillary acidic protein (GFAP) in the same cell. These double-stained cells are detected between day 5 and day 13 after seeding. These cells could be morphologically identified as oligodendroblasts. At 5 days in culture about 10% of the cells containing CAII also contained GFAP. At 11 days only 2% preserved this property. After 13 days in culture GFAP was only localized in typical astrocytes and CAII in oligodendroglial-like cells. The presumption that the immature glial cells, which contained specific markers of astrocytes and oligodendrocytes, became in our culture conditions essentially oligodendroglial cells is discussed.