Two @entity2235 (SV40)-transformed cell lines from the XXXX striatum and mesencephalon presenting astrocytic characters. III. A light and electron microscopic study.

@entity2235 @entity19 @entity1138 @entity70881 @entity5393
In two preceding papers we described the cloning of two astrocytic cell lines by @entity2235 (SV40) transformation of embryonic @entity19 mesencephalon (F7-Mes) and striatum (F12-Str). The characterization of these lines as belonging to the astrocytic lineage is based on pharmacological, immunocytochemical and physiological data. Here we present quantitative and qualitative data on the morphological aspects of these two astrocytic clones observed under light and electron microscopy. We show that the clones present ultrastructural characters reminiscent of the morphology of young astrocytes. On one hand, they are rather similar to primary astrocytes in culture; on the other, they differ both from a clonal fibroblastic cell line ( @entity70881 ) and from embryonic @entity19 fibroblasts in primary culture. These astroblastic clones display 4 morphologically different cell populations which we called types I, II, III and IV. Types II and III are very similar and represent the most predominant cells; their morphologies strongly remind of that of astroblasts. Type I corresponds to glioblasts and does not account for more than 15-20% of the total population. Type IV, which is very similar to differentiated velamentous astrocytes, normally represent ca. 5% of the cells. However, when the transformed cells are treated with @entity1138 or @entity1138 + @entity5393 ( @entity5393 ), the proportion of type IV cells increases very much (up to more than 50% of the cells) while types I, II and III become less numerous. Morphological analysis therefore confirms that the two cell lines derived from the SV40 transformation of 14-day-old embryonic mesencephalic and striatal cells belong to the astrocytic lineage. Moreover, it seems that they can differentiate in vitro in cell culture conditions either spontaneously or under the action of pharmacological treatments known to enhance normal astrocyte maturation.
