Fig. 3. The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway inhibition partially nullified the induction of insulin-like growth factor-1 (IGF-1) on rat bone marrow mesenchymal stem cell osteogenic differentiation. (A) Alkaline phosphatase (ALP) activity of cells was detected 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) levels were measured by Western blot. The cellular experiments were independently repeated three times. Data were expressed as the mean±SD. One-way ANOVA was adopted for comparisons among groups, followed by Tukey’s test. DMSO: dimethyl sulfoxide, GAPDH: glyceraldehyde-3-phosphate dehydrogenase. *p<0.05, **p<0.01.