Concentrated growth factor promotes Schwann cell migration partly through the integrin β1-mediated activation of the focal adhesion kinase pathway

Nerve injury is a serious complication associated with dental implant surgery. Following nerve injury, the migration of Schwann cells (SCs) supports nerve regeneration. Concentrated growth factor (CGF) belongs to a new generation of biomaterials that contain fibrin matrix, as well as a number of growth factors that affect the migration of various types of cells, including endothelial cells and cancer cells. To the very best of our knowledge, there are no available studies to date on the promoting effect of CGF on the migration of SCs. Thus, the aim of the present study was to characterize the structure of CGF and growth factor release, examine the effects of CGF on the migration of SCs, and to examine the role of integrin 1 and the focal adhesion kinase (FAK) pathway in the CGF-induced migration of SCs. For this purpose, CGF was prepared by centrifuging rat venous blood, which produced a fiber-like matrix capable of releasing transforming growth factor-1 (TGF-1) over a sustained period of time (at least 13 days). The soluble component of CGF was used to produce conditioned media to treat the SC cells in culture. The results demonstrated that CGF promoted the migration of SCs and increased the expression of integrin 1. These effects appeared to involve FAK phosphorylation, which occurred downstream of integrin 1 activation. The short-interfering RNA (siRNA)-mediated downregulation of integrin 1 expression did not block the ability of CGF to promote the migration of SCs. These data suggest that CGF promotes the migration of SCs partly through the integrin 1-mediated activation of the FAK pathway.