Characteristics of UC-MSCs. (a) Cell culture of passage 3. Original magnification × 40. The cells had a fibroblast-like morphology. (b) Flow cytometric analysis of surface-marker expression on UC-MSCs. They were negative for CD14, CD45, CD34 and HLA-DR, but positive for CD44, CD73, CD90 and CD29. The dotted line is the isotype control. (c) Oil red O staining of UC-MSCs after the induction of adipogenic differentiation for 21 days. Arrows indicate lipid roplets. Original magnification × 40. (d) Osteogenic differentiation of UC-MSCs staining for alkaline phosphatase. Arrows indicate the accumulation of intracytoplasmic alkaline phosphatase of osteoblast. Original magnification × 40.