Expression of substance P receptor in bone marrow mesenchymal stem cells during osteogenic differentiation

Objective To compare the expression of substance P (SP) receptor in rat bone marrow mesenchymal stem cells (BMSCs) according to the stage of osteoblast differentiation. Methods The rBMSCs were isolated in vitro using whole bone marrow adherence method, and classified as osteoblast-in-duced group and non-induced group. In the different periods of culture (1,2, and 3 weeks) , identification of osteoblasts was performed by immunocytochemistry and reverse transcriptase polymerase chain reaction ( RT-PCR). The expression of the SP receptor was detected by using Western blotting and RT-PCR. Results There was SP receptor expression in the cultured BMSCs and osteoblasts. RT-PCR demonstrated that the expression of SP receptor in osteoblast-induced group was lower than in non-induced group at the week one (P<0.05 ) , but significantly increased at the week three(P<0.05 ). In osteoblast-induced group the expression of SP receptor was higher than in non-induced group at the same time point (P <0.05), and that was significantly increased time-dependently at the week three (P<0.05). Conclusion SP receptor exists in the BMSCs and osteoblasts. SP receptor expression was significantly increased at late-stage of osteogenic differentiation. Key words: Substance P;  Bone marrow;  Mesenchymal stem cell;  Osteoblast;  Differentiation