Figure 4. Multi-differentiated MSCs. Lipid droplets appear in the cytoplasm at the fourth day (A; 20×), and large numbers of lipid droplets (red) in MSCs are shown with Oil-red O staining after adipogenesis induction (B; 20×). Under osteogenic culture conditions, MSCs become flat and wide (C; 20×) and calcium nodules (black) can be detected in the cytoplasm with von Kossa staining (D; 20×).