MSC characterization. (A) Cells were analyzed for surface expression of MSC markers CD44, CD73, CD90, and CD105; endothelial marker CD31; hematopoietic markers CD34 and CD45; and phagocytic lineage markers CD11b, CD115, and CD206 by flow cytometry analysis (leftmost curves correspond to isotypic controls). (B) Photograph of differentiated MSCs grown in osteocytic differentiation medium and adipocytic differentiation medium for 4 weeks, stained, respectively, with Alizarin Red (left) and Oil Red O (right); scale bar = 50 μm. (C) Relative mRNA expression of osteoblastic differentiation markers runt-related transcription factor 2 (RUNX2), bone-specific alkaline phosphatase (ALPL), and osteocalcin (OC). Expression levels in normal MSCs at 4 weeks were used as a reference value. Error bars represent 1 SD. (D) Flow cytometry analysis of passage 3 MSCs stained with CFSE and allowed to proliferate for 7 days before flow cytometry analysis. (E) Scanned autoradiogram of a Western blot performed for APE-1 expression analysis in passage 3 MSCs, with β-tubulin expression used as a loading control.