FIG. 4.

Various adult and/or immortalized skeletal progenitor cell types in micromass. BF micrographs of immortalized mouse bone marrow-derived mesenchymal stem cells (MSCs) (D1), immortalized mouse embryonic fibroblasts (C3H10T1/2), and primary rat bone marrow-derived MSCs (rBM-MSC) cultured in micromass for 3 days. Mesenchymal condensations, indicated by local increases in cell density (Fig. 1), have not formed in any culture. Although the rat MSC micromass culture appears to show inhomogeneities in cell density in the BF image, a micromass stained with DAPI (right) shows homogeneous cell density. For all BF images, scale bar is 100 μm. For fluorescent DAPI image, scale bar is 200 μm. Color images available online at www.liebertpub.com/teb