RESUMO
Objective To study the molecular pathway of osteoblastic differentiation induced by substance P (SP), a neurotransmitter. Methods Mesenchymal stem cells were isolated and cultured, and treated with SP or its receptor (NK1) antagonist to induce osteoblastic cell differentiation, respectively. Alkaline phosphatase activity was determined; Osterix gene expression was detected by RT-PCR after 1-2 weeks for three times. The data of each culture condition were analyzed using SPSS12.0 statistical software to determine whether the differences between conditions were significant. Results After 4-5 days' culture, bone marrow stromal cells became spindle-shaped, triangular or polygonic. They covered the plate surface, formed extensive cell sheets in each group after 11-12 days of culture, and then induced differentiation to osteoblast. SP up-regulated the important transcription factor Osterix gene expression significantly (P<0.05). Conclusion The up-regulation of Osterix gene expression by SP may stimulate osteoblastic cell differentiation. SP's regulation depends on its receptor NK1.