Fig. 4.

mRNA expression of the BMP receptor in BMSCs. BMSCs were treated with CM or OM with or without BMP-2. mRNA was extracted from cells on day 3, 6, and 9 and analyzed by RT-PCR. GADPH mRNA was used as an internal control to normalize the amount of RNA. The relative expression level of mRNA was depicted as the ratio of the density of mRNA to GADPH mRNA at the same time point. The results correspond to a representative of three experiments. RT-PCR analysis revealed that the osteogenic medium significantly induced BMPR-IA and BMPRII expression in BMSCs after three days of stimulation, while BMP-2 significantly induced BMPRIA and BMPRII in BMSCs after nine or six days of stimulation, respectively. ^*Compared with CM at the same time point, p < 0.05. ^†Compared with BMP-2 at the same time point, p < 0.05. CM, control medium; OM, osteogenic medium; BMP-2, bone morphogenetic protein-2; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; BMPRIA, type IA receptor of BMPR; BMPRII, type II receptor of BMPR; RT-PCR, reverse transcription-polymerase chain reaction; BMSCs, bone marrow stromal cells.