Sdf-1 impact on bone marrow mesenchymal stem cells. (A) Western blotting analysis of CXCR4, CD9, and tubulin in the whole population of bone marrow-derived mesenchymal stem cells (BM-MSCs) as well as of CXCR4+ and CXCR4– BM-MSCs fractions fractions. (B) Quantitative RT-PCR analysis of CXCR4 and CD9 mRNA in BM-MSCs in control and Sdf-1-treated BM-MSCs. (C) Western blotting analysis of CD9 and tubulin in control and Sdf-1-treated (Sdf-1) BM-MSCs. (D) Migration of BM-MSCs in Sdf-1 gradient. The number of cells that migrated from the inserts was counted. (E) Percent of hybrid myotubes formed in co-culture of C2C12 myoblasts and control or Sdf-1 pretreated BM-MSCs. (F) Co-culture of C2C12 myoblasts and control or Sdf-1 pretreated BM-MSCs (green, localisation of β-galactosidase; blue, nuclei). Bar = 50 μm. CXCR, CXC chemokine receptor. *P <0.05. Error bars indicate standard deviation.