Efficacy of mechanical vibration in regulating mesenchymal stem cells gene expression.

This study aimed at investigating the expression of osteoblast and chondrocyte-related genes in mesenchymal stem cells (MSCs), derived from rabbit adipose tissue, under mechanical vibration. The cells were placed securely on a vibrator's platform and subjected to 300 Hz of sinusoidal vibration, with a maximum amplitude of 10 μm, for 45 min per day, and for 14 consequent days, in the absence of biochemical reagents. The negative control group was placed in the conventional culture medium with no mechanical loading. The expression of osteoblast and chondrocyte-related genes was investigated using real-time polymerase chain reaction (real-time PCR). In addition, F-actin fiber structure and alignment with the help of actin filament fluorescence staining were evaluated, and the level of metabolic activity of MSCs was determined by the methyl thiazolyl tetrazolium assay. The real-time PCR study showed a significant increase of bone gene expression in differentiated cells, compared with MSCs (P < 0.05). On the other hand, the level of chondrocyte gene expression was not remarkable. Applying mechanical vibration enhanced F-actin fiber structure and made them aligned in a specific direction. It was also found that during the differentiation process, the metabolic activity of the cells increased (P < 0.05). The results of this work are in agreement with the well-accepted fact that the MSCs, in the absence of growth factors, are sensitive to low-amplitude, high-frequency vibration. Outcomes of this work can be applied in cell therapy and tissue engineering, when regulation of stem cells is required.