Mechanical Vibration Regulates Differentiation and Proliferation of Neural Stem Cells

For the regeneration of the central nervous system, neural stem cells have been proposed as graft donors. Conventional studies have used biochemical factors to induce their differentiation into neurons and to enhance axon elongation. However, few studies have been reported on the effects of mechanical factors on neural stem cells. In this study, we show that mechanical vibration directs the differentiation of neural stem cells into neuronal cells, elongates their axons, and increases the number of differentiated cells. We found that the 25 Hz and 0.5 G vibration promoted the differentiation of neural stem cells into neuronal-marker-positive cells expressing neurofilament heavy polypeptide by 2.5-fold compared to the control conditions and increased the number of differentiated cells with axons longer than 10 μm by 1.5-fold at 7 days of culture. Furthermore, we found that the total number of differentiated and undifferentiated cells in the vibration condition reached 2.9-fold more than the control condition and that this effect depended on the frequency and acceleration. We anticipate our system to facilitate further studies using mechanical vibration such as regenerative therapy using neural stem cells and the elucidation of differentiation mechanisms in neural stem cells.