Fig. 4

Blocking the cAMP-PKA signaling pathway inhibits ERK1/2 and suppresses hBMSC osteogenic differentiation. a Histochemical staining and b total absorbance measurements of ALP during early hBMSC osteogenic differentiation stimulated with SKF-38393, PKA inhibitor (H-89), and SKF-38393+ H-89 (n = 3 for all groups). c Alizarin Red S staining and d total absorbance measurements during late hBMSC osteogenic differentiation stimulated with SKF-38393, H-89, and SKF-38393+ H-89 (n = 3 for all groups). e Quantitative RT-PCR analysis of osteogenic gene expression during hBMSC osteogenic differentiation stimulated with SKF-38393, H-89, and SKF-38393+ H-89 (n = 3 for all groups). f Immunoblot analysis of Runx2, phosphorylation, and total ERK1/2 expression during hBMSC osteogenic differentiation stimulated with SKF-38393, H-89, and SKF-38393+ H-89 (n = 3 for all groups). The results are shown as the mean ± standard error. Statistical significance was assessed by one-way ANOVA test; *P < 0.05; **P < 0.01; ***P < 0.001