Runx2 and Osterix Gene Expression in Human Bone Marrow Stromal Cells Are Mediated by Far-Infrared Radiation

Runx2 and Osterix are the key transcription factors initiating and regulating the early osteogenesis and late mineralization of bone. To investigate whether the expression of these osteogenic genes in human bone marrow stromal cells (hBMSCs) was regulated by physical stimulation, far infrared (FIR) was applied to this present work. hBMSCs were cocultured and physically separated with the their adjacent cell, human osteoblasts (hOBs) in a transwell system. Both cells were placed onto 200-mg FIR ceramic powders packed into a plastic bag for uniform FIR irradiation. 0-, 30-, 60-, and 120-min treatment of FIR irradiation were performed inside an incubator. Each group was fully wrapped by foils to prevent FIR interruption. The electrophoretic RT-PCR data showed that hBMSCs exhibited higher gene expression of Runx2, Osterix and collagen type I under 120-win/day FIR treatment at day 14. Histochemical staining results also revealed that FIR-treated hBMSCs expressed more ALP and calcium deposits after 28-day exposure. It suggested that appropriate physical stimulus may be an alternative tool for the control of osteogenic differentiation in hBMSCs in vitro.