Fig. 4

EPCs promotes the osteogenic differentiation of MSCs. a Osteogenic differentiation was determined by ALP staining at day 7, 14, and 21 days after osteogenic differentiation induced. Data represents the mean ± SD of n = 3 samples. b Expression of the osteogenic genes OPN, BSP, and Runx2 were measured by qRT-PCR at the day 14 after osteogenic differentiation induced (n = 3) *p < 0.05. c EPCs promotes activation of the MAPK signaling pathway of MSCs. p38, p-p38, ERK1/2, p-ERK1/2, JNK, and p-JNK expression were examined by western blotting, *p < 0.05. d Densitometry of protein levels of p38, p-p38, ERK1/2, p-ERK1/2, JNK, and p-JNK by immunoblotting, β-actin was used as the internal control. Data are presented as the mean ± SD. And e MKK6, TAB1, and p38 mRNA expression were measured by qRT-PCR (n = 3), *p < 0.05. Co-MSCs, co-cultured MSCs; MSCs, monolayer cultured MSCs