Influence of rearrangement of actin cytoskeleton on the overall material properties of ATDC5 cells during chondrogenesis

Studies show that when chondrocytes are cultured in 2D, they lose their phenotype. This change is reversed when the cells are embedded in a 3D culture system such as in agarose gel. Previous experiments in our lab showed that when prechodrocytic cells were embedded in agarose, chondrogenesis was triggered in these cells. This work attempts to understand the mechanical implications of this behavior. It also provides an estimate of the sensitivity of the apparatus that would be required to carry out compression loading experiments of gel-cell constructs that can distinguish between pre-chondrocytes and chondrocytes.;ATDC5 cells were cultured in 3D for 12 days and fluorescent images of the actin cytoskeletal structure of the cells were obtained. A major reorientation of the cytoskeletal structure (from stress-fiber to punctate appearance) was observed. This data was then used to construct a Finite Element model of cell. The cell was considered as a composite matrix and the actin as the embedded fibers. Radial deformations of the cell (difference in the corresponding undeformed and deformed radii of the cell at a particular angle w.r.t. loading axis) were calculated for 5 sets of experimental data. (Abstract shortened by UMI.)