The Primary Study On The Mechanism Of Osteoblast Proliferation Signal Transduction Under Stress Action

People had found the importance of stress in bone rebuilding before one century, but it is not clear how bone response to the stress and transfer the signal to the cell then regulate the bone rebuilding. Different scholars used different methods and showed that: how cell responds to the stress depends on the magnitude of the stress that the cell endured. There are some investigations showed that stress can stimulate the cell proliferation, but some scholars thought that the stress would inhibit the cell proliferation.We applied controlled flow fluid stress to monolayer osteoblast cultured in vivo by using the flow chamber system designed by ourself and try to find the most proper stress through examining the change of cell proliferation after different stress level were applied. We used MTT method to examine the cell proliferation after stress were applied and found that the regulation of stress to the bone rebuilding related to the flow fluid stress induced by the stress. Low shear stress (6dyne/cm2) has no effect on cell proliferation; medium shear stress (12dyne/cm2)has obvious effect on cell proliferation; high shear stress (18dyne/cm2) will inhibit cell proliferation.We investigated the c-fos protein expression in nucleolus after the shear stress applied and found c-fos protein expression. The c-fos protein proper expression can lead to the cell extending and the cell matrix protein composing to adapt to the shear stress. It provided the data to research how cell transfer the shear stress signal and it is useful to find the influence of shear stress to the cell function and metabolism.We carried out a primary study of shear stress activated K+ channel in osteoblast by using clamp patch technology . The result supported that shear stress sensitive ion channel was really existed on membrane of osteoblast. While shear stress was applied k+ current increased significantly in amplitude as compared with shear stress. Shear stress can influence the Ca2+ in cell by affect the K+ channel. This study is useful to the later research on signal transduction of osteoblast.