Osteogenic Differentiation of Human Mesenchymal Stromal Cells Promoted by Acoustic Vibration

Abstract

In order to verify whether differentiation of human stem cells toward bone tissue is promoted by higher acoustic vibration (≥90 Hz), human mesenchymal stromal cells (hMSCs) were mechanically stimulated with vibration (400 and 800 Hz, 0.3 g acceleration) for 30 min every 24 h for 7 or 14 days in vitro. Cells were seeded in osteogenic medium, which enhanced differentiation towards bone tissue. The osteogenic differentiation of hMSCs under the vibrated and non-vibrated conditions was assessed by examining mRNA expression of various osteoblast-associated markers (ALP, Runx2, osterix (Osx), collagen type I (Col I) and osteopontin (OPN)), and matrix mineralization. Our results indicated that acoustic vibration at frequency 800 Hz was more favorable for hMSCs osteogenic differentiation: the gene expression involved in osteogenic differentiation was significantly increased after 7 and 14 days, and deposition of calcium was almost 1.5-fold. Further studies are necessary to verify the long-term viability and commitment to osteogenic differentiation of hMSCs in vitro and in vivo, and select the optimum sensitive acoustic frequency, with the purpose of determining whether acoustic vibration could become a novel means to treat osteoporosis.