Figure 4. Matrix stiffness regulates the cellular morphology. (A) hUC-MSCs were cultured on matrix gels with different stiffness of 13-16kPa and 62-68 kPa. Compared with the control group, more cells on 13-16kPa were shaped like round dots on the 1st day, and like short columnar cells on the 7th day. On the 14th day, the morphology of cells was like cardiac muscle cells. Cells on 62-68 kPa were in the shape of polygon on the 1st day, and were in the shape of long spindle on the 7th day and the 14th day. Scale bar = 100μm. (B) Aspect ratio of each group. (C) Area of each group. Both aspect ratio and area of cells on matrix of 13-16kPa were the lowest, and the control were the largest within them. *P<0.05, **P<0.01, ***P<0.001. n=3.