Fig. 1. Insulin-like growth factor-1 (IGF-1) induced rat bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation. (A) Alkaline phosphatase (ALP) activity of cells was assessed by ALP staining. (B) Calcification level of cells was determined by Alizarin Red staining. (C) Runt related protein 2 (RUNX2), osteocalcin (OCN), and osterix (OSX) protein levels in BMSCs were measured by Western blot. The cellular experiments were independently repeated three times. Data were expressed as mean±SD. Comparisons between the two groups were performed by independent sample t-test. GAPDH: glyceraldehyde-3-phosphate dehydrogenase. *p<0.05, **p<0.01.