CONTROL OF APOPTOSIS AND DIFFERENTIATION OF CULTURED NEURAL STEM CELLS BY MECHANICAL VIBRATION

摘要

In this study, sinusoidal inertia force was applied to cultured neural stem cells and the effects of mechanical vibration on the cells were investigated. Neural stem cells which were obtained from the hippocampus of an adult Fischer rat were seeded in culture plates at the density of 2.5 × 10~5 cells/ml. After cells were cultured for one day and adhered on the cultured plate, vibration groups of the culture plates were set on the aluminum plate of the experimental setup and cultured under sinusoidal excitation in another CO_2 incubator separated from non-vibration groups of the culture plates. Acceleration amplitude was set to 0.25 or 0.5 G and frequency was set to 12.5, 25, or 50 Hz. Time evolution of cell density was obtained by counting the number of cells with a hemocytometer. The expression of Akt, phosphorylated Akt, MAPK, and phosphorylated MAPK was detected by western blotting analysis to understand the mechanism of cell proliferation. Gene expression of MAP-2, neurofilament-H, GFAP, and nestin was detected by a real-time RT-PCR method to obtain a ratio of differentiation of neural stem cells to nerve or glia cells. The results to be obtained are as follows. The mechanical vibration at 25 Hz is most effective on cell proliferation of the present experimental conditions at 0.25 G. The enhancement of cell proliferation is probably caused by the suppression of apoptosis. The differentiation of the neural stem cells depends on acceleration amplitude and the mechanical vibration may maintain some properties of stem cells.