The differentiation of human adipose-derived stem cells (hASCs) into osteoblasts is promoted by low amplitude, high frequency vibration treatment

Several studies have demonstrated that tissue culture conditions influence the differentiation of human adipose-derived stem cells (hASCs). Recently, studies performed on SAOS-2 and bone marrow stromal cells (BMSCs) have shown the effectiveness of high frequency vibration treatment on cell differentiation to osteoblasts. The aim of this study was to evaluate the effects of low amplitude, high frequency vibrations on the differentiation of hASCs toward bone tissue. In view of this goal, hASCs were cultured in proliferative or osteogenic media and stimulated daily at 30 Hz for 45 min for 28 days. The state of calcification of the extracellular matrix was determined using the alizarin assay, while the expression of extracellular matrix and associated mRNA was determined by ELISA assays and quantitative RT-PCR (gRT-PCR). The results showed the osteogenic effect of high frequency vibration treatment in the early stages of hASC differentiation (after 14 and 21 days). On the contrary, no additional significant differences were observed after 28 days cell culture. Transmission Electron Microscopy (TEM) images performed on 21 day samples showed evidence of structured collagen fibers in the treated samples. All together, these results demonstrate the effectiveness of high frequency vibration treatment on hASC differentiation toward osteoblasts. (C) 2011 Elsevier Inc. All rights reserved.