Mesenchymal stem cells were spindle-like and expressed certain protein markers on the cell surface. (A) Cell shape and growth states were similar between bone marrow mesenchymal stem cells (BM-MSCs) and umbilical cord mesenchymal stem cells (UC-MSCs) in vitro. (B) As shown in the overlay histograms, five cell surface markers of BM-MSCs were verified: CD29 (FITC, green), CD44 (FITC, green), and CD90 (FITC, green), which were positive, and CD34 (PE, orange) and CD45 (PE, orange), which were negative. (C) Four cell surface markers of UC-MSCs were verified: CD90 (FITC, green), which was positive, and CD31 (APC, red), CD34 (PE, orange), and CD45 (PE, orange), which were negative. FITC, fluorescein isothiocyanate; PE, phycoerythrin.