The Variation Of The CTF Of The Mice Stem Cells In Differentiation

Cells generate internal tensile forces through actomyosin interactions and actin polymerization,they exert tractions on extracellular matrix. This internal tensile forces is referred to as cell traction force(CTF). CTF is regulated by intracellular proteins such as alpha-smoothmuscle actin (α-SMA) and transforming growth factor-β(TGF-β), it is an important physical parameter and is vital.for many biological processes, including metastasis, inflammation, wound healing,angiogenesis, cell shape maintenance, and mechanical signal generation. The study of cell traction forces enables us to better understand these cell and the mechanisms of the growth. In this study, Researcher want to find the mechanism of differentiation through measureing the CTF of some stem cells before and after differentiation.Object:to find the mechanism of differentiation through measureing the CTF of ACL Patella tendo,Achilles's tendon stem cells before and after differentiation.,and provide new enlighten and thohght for physiology and pathology.Methods:1,Culture cells. Obtaining the cell needed and culturing them in CO2 incubator.After three to four days, remove the cell which not anchorage. Observating the cells with inverted microscope and picking the growth of cells cloned, once every three days, until most cells has good state, take them and determinate cell traction force.2,The CTFM (Cell Traction Force Microscopy) methods, which use elastic PAG substrate in measuring CTF, using fluorescent beads when fabricate the PAG. and the displacement field can be determined based on the movement of markers on the surface of the PG,we could obtain a pair of "force loaded" and "null force" microscopy images,which is the images we obtain when the cells adhere on substrate and be off.finally, determining the CTF by using the MATLAB and the program which workout.In all, the approach involve three major steps. The first step is to fabricate elastic PG substrate with a flat surface, using fluorescent beads when fabricate the PG.The next step is to obtain a pair of "null force" and "force loaded" microscopy images, from which the displacement field is determined based on the movement of markers on the surface of the PG substrate.The last one is analyse the images and determining the CTF by the MATLAB.2. Measureing a-SMA of ACL stem cells before and after differentiation by western bloting.Results:CTF of the mouse stem cells were decreased obviously after differentiation when these cells change significantly in morphology. The average of magnitude of CTF were reduced by 30%. The amount ofα-smooth muscle actin (α-SMA) also be reduced correspondingly. This suggest that the structure and component of stem cells have changed significantly and to a certain extent the expression of a gene.