The Effect Of Matrix Stiffness On Umbilical Cord Mesenchymal Stem Cells To Proliferation, Adhesion And Differentiation

Umbilical cord mesenchymal stem cells(UC-MSC) is a multifunctional stem cells present in the newborn umbilical cord mesenchymal, having an easy adherent growth, a rich source and other advantages. Because of its strong proliferation, differentiation potential, immune suppression and regeneration in vivo, it has been widely used in tissue engineering research and clinical treatment. This paper describes that mechanically separate the matrix umbilical cord, using the method of enzyme digestion and tissue explant, getting plenty of fresh inter-core umbilical cord mesenchymal stem cells(UC-MCS). After identification, these cells can be stably passaged. By flow cytometry and immunofluorescence analysis of surface markers,we found mesenchymal cells express CD44, CD73, CD90 and CD105 and negatively express CD34,CD45. When cultured in differentiation medium, they can differentiate into adipocytes and osteoblasts.Current research indicates that chemical and mechanical factors have been widely used to study the effects on cell behavior. Many studies using controllable physical factors that stimulate stem cell research on osteogenesis, these studies suggest that physical stimuli can induce directed differentiation into bone. Now physical factors have been studied include hydrodynamic factors, biomechanical factors, photochemical and electromagnetic factors and other factors. Among these, extracellular matrix is the most obvious factors because of its effects on cell behavior, simple, controllable and has been widely studied. Different literature suggests that the growth in extracellular matrix of different stiffness of the mesenchymal stem cell exhibit different differentiation directions. However, whether the stiffness of the matrix can affect the behavior of other cells of proliferation, adhesion and spreading, has not be studied. whether the biological behavior of mesenchymal stem cells would affect differentiation has not been studied in detail demonstration.In this paper, primary isolated umbilical cord mesenchymal stem cells will be cultured in adjustable stiffness polyacrylamide gel, and gel coated with fibronectin. Depending on the different concentration of bisacrylamide can obtain the Young’s modulus 13-16 kpa, 35-38 kpa, 48-53 kpa and 62-68 kpa of hydrogel. The results show that because of the different stiffness of the matrix, the proliferation and adhesion of the umbilical cord mesenchymal stem cells were exhibit different situation, while the capacity of the cells is spreading in 35-38 kpa, 48-53 kpa strongest. Real-time quantitative PCR results showed that the soft substrate can promote cell into adipogenic differentiation, evidence of increased expression PPARγ, C/EBα. Cells tend to differentiate into muscle, evidence of increased expression of Desmin and MOYG on 35-38 kpa, 48-53 kpa. In the high stiffness of the matrix,cells tend to differentiate into bone, evidence of increased expression ALP, type I collagen, osteocalcin, Runx2 gene. So, we consider the in a softer matrix, cell can easily proliferate and adherent, and be promoted into adipogenic differentiation; and stiffer matrix will hinder cell proliferation and adhesion, the cells may be promoted the osteogenic differentiation.