Comparison of osteogenic medium and uniaxial strain on differentiation of endometrial stem cells

Mechanotransduction plays a pivotal role in remodeling and repair of skeletal tissues. This mechanism has been widely used in bone tissue engineering especially under in vitro conditions. To date, various stem cells have been used for this purpose. The present study was the first to evaluate the effect of mechanical loading on differentiation of human endometrial stem cells (hESCs) to osteoblasts.

Adhesion of endometrial stem cells after isolation and culture on a silicone membrane covered with collagen was evaluated under scanning electron microscope (SEM). Twenty-four hours after cell culture on the membrane and ensuring appropriate cell adhesion, a group of cells in a conventional culture medium received 3% static uniaxial strain. In the positive control group, cells cultured on the membrane were placed in an osteogenic medium without receiving any mechanical strain. The negative control group was placed in a regular medium and received no strain either. Two weeks later, cultured cells were evaluated for expression of osteogenic markers using immunofluorescence staining and real-time polymerase chain reaction (PCR). Data of real-time PCR was analyzed by ANOVA. P < 0.05 was considered statistically significant.

SEM analysis revealed adequate cell adhesion to the membrane after 24 h. Two weeks after loading, expression of markers in the positive control group was significantly higher compared to test group.

We can conclude that static uniaxial strain exerted on hESCs results in their differentiation to osteoblasts. However, this magnitude of static strain in the tested time period cannot yield excellent differentiation when compared to the osteogenic medium.