FIG. 2.

Astrocytes exhibited unique profiles of morphologies dependent upon in vitro growth environment. Representative confocal images of primary astrocytes grown on 2D collagen-coated coverslips (A, C, E) or within 3D collagen gels (B, D, F) for 4 days in serum-containing media show immunoreactivity for the astrocyte marker, GFAP, as shown in red and cell nuclei are labeled with DAPI (blue). Multiple morphologies were observed in the GFAP⁺ cells: round, without distinct processes or projections (A, B), bipolar cells, which had two opposing processes (C, D), and stellate cells, with multiple processes emerging from a centrally located soma (E, F). The stellate cells resembled mature astrocytes in vivo. (G) Distribution of morphologies in 2D and 3D cultured substrates. Asterisks denote significant differences between the percentages of cells grown in 3D exhibiting each morphology compared with those on 2D substrates (p < 0.001 level). Scale bar: 20 μm. Please note that the cell in (B) is much smaller than the others. Color images available online at www.liebertpub.com/tea