Abstract
This paper describes the mechanism of cell proliferation promotion by mechanical vibration focusing on an integrin. Integrins are transmembrane receptors that are the bridges for cell-extracellular matrix interactions and related to cell proliferation and differentiation. Integrin α5β is the primary receptor for fibronectin which exists in extracellular matrices. If integrin α5β is a mechanosensor of mechanical vibration, cells lacking β1 integrin subunit are insensitive to mechanical vibration and their cell proliferation is not promoted by vibration although its promotion was reported in the conventional studies of osteoblast-like cells. Here we show the effects of mechanical vibration on GD25 which is a fibroblast-like cell lacking β1 integrin subunit. When GD25 cells were cultured under the mechanical vibration of 0.5 G and 12.5 Hz, the saturated cell density was significantly higher than the control group although β1 integrin subunit was lacked from GD25 cells. The multilayer formation of GD25 cells was observed by fluorescent microscopy and the number of the layer in the vibration group was higher than that in the control group. This indicates that the cell proliferation promotion under mechanical vibration may be related to the multilayer formation.
