FIG. 4.

Characterization of trilineage differentiation potential of CDCs and CMSCLC at passage 3. Representative brightfield images, from three different patient tissue samples of (A) CDC and (B) CMSCLC after 28 days in osteogenic culture conditions and before alizarin red staining, demonstrate cellular proliferation and matrix deposition. Images of cells from the same samples but after being stained with alizarin red staining reveal mineralization of osteoid matrix within osteogenic cultures differentiated from CDCs (C), whereas (D) there is no mineralization of culture matrix when CMSCLC were differentiated. Images of CDCs (E) and CMSCLC (F) after 21 days under adipogenic culture conditions stained with oil red O. Note the presence of red stained cells in both cultures. Images of cryosections of cell aggregates formed under prochondrogenic culture conditions after 14 days and after staining with safranin O (counterstained with hematoxylin and fast green) for CDCs (G) and CMSCLC (H). Note that while cell aggregates formed for both CDCs and CMSCLC, chondrogenesis did not occur as evidenced by the absence of safranin O staining for sulfated glycosaminoglycans. Histological evaluation of cell aggregates shows lack of extracellular matrix deposition between cells and hence weak tissue structure. All scale bars = 100 μm. BM-MSCs are shown after culture using the same differentiation protocols as for CDCs and CMSCLC and stained with alizarin red (I), oil red O (J), and safranin O (K). Note BM-MSCs can differentiate to all three lineages. Scale bars for (I, J) = 100 μm. Scale bar for (K) = 400 μm. BM-MSCs, bone marrow-derived MSCs. Color images are available online.