Adipogenic differentiation of human MSCs. (A) MSCs were induced into the adipogenic lineage and at day 5, adipogenesis was assessed by oil red O staining of lipid droplets. (B) At day 5, unstimulated control MSCs (NC) did not form any lipid droplets. (C) At day 15, the number of oil red O stained lipid droplets was increased, (D) whereas the control cultures did not form any lipid droplets. (E) Real-time polymerase chain reaction revealed that the adipogenic marker genes peroxisome proliferator-activated receptor gamma (PPARG), and (F) fatty acid binding protein-4 (FABP4) were expressed significantly higher in induced cultures than in primary (day 0) or control (not stimulated) cultures (*P<0.05, **P<0.01, ***P<0.001). Bar: 200 μm. NC, negative control.