Effect of substrate stiffness on the functions of rat bone marrow and adipose tissue derived mesenchymal stem cells in vitro.

Regenerative medicine treatments that combine the use of cells and materials may open new options for tissue/organ repair and regeneration. The microenvironment of mesenchymal stem cells (MSCs) strictly regulates their self-renewal and functions. In this study, when rat bone marrow derived MSCs (rBMSCs) and rat adipose tissue derived MSCs (rAMSCs) in passages 2-4 were cultured on different substrates, they presented the cellular functions to be dependent of substrate stiffness. The cells attached better on the softer substrate than on the stiffer one. The substrate stiffness had no significant influence on the proliferation of those cells. However, the substrate stiffness significantly promoted the osteogenic differentiation of the two kinds of stem cells. Furthermore, rBMSCs cultured on the same stiffness expressed more osteoblast-related markers than rAMSCs. In addition, combined biomaterials and biochemical reagents treatment yielded a stronger effect on osteogenic differentiation of MSCs than either treatment alone. These results have significant implications for further extending our capabilities in engineering functional tissue substitutes.