Characterization of RA-hMSCs. (A) Cell surface markers for RA-hMSCs were identified by FACS analysis, and were identified in cells positive for CD44, CD90, and CD105 and negative for CD34 and CD45. Data were presented as mean% ± SEM. (B) RA-hMSCs were differentiation induced into osteogenic and adipogneic lineages. Osteogenic induction was assessed by Alizarin red S staining of calcium deposition formation and adipogenic induction was assessed by Oil-red O staining of accumulated lipid vacuoles (scale bar, 100 μm).