mRNA Expression after 5 days by real time PCR. There were four groups: Group 1: MSC co-cultured with EC (Co); Group 2: MSC induced by osteogenic stimulatory medium (OM); Group 3: MSC in mono-culture without osteogenic stimulatory supplements (MSC) and Group 4: EC only (EC). Results were reported as fold changes ± fold-difference (2-ΔΔCt ± 2-(ΔΔCt ± SD)). The y-axis showed mRNA level in logarithmic scale for ALP, RunX2 and Col I. A significant upregulation of ALP expression was found in MSC/EC co-cultures compared with MSC alone. All the data were normalized with endogenous control GAPDH. ** P < 0.01 * P < 0.05.