単軸圧縮試験による石灰化過程のヒト間葉系幹細胞由来スフェロイドの弾性及び粘弾性評価

抄録

Recent years have seen an increased interest in three-dimensional (3D) cell culture models as they better represent in vivo conditions than two-dimensional (2D) cultures. Utilizing human mesenchymal stem cells, we have fabricated spheroids and demonstrated an increase in osteocyte markers in the early phase compared to the 2D culture as well as mineralization in the late phase. Assessing their mechanical properties and behavior is crucial to verify their bone formation potential in vitro. In this study, we conducted uniaxial compression tests to measure Young's modulus of the spheroids and evaluated their behaviors over time after compression in order to evaluate their elasticity and viscoelasticity. Our results revealed that Young's modulus of spheroids cultured for 35 days was 2.5 times higher than those cultured for 2 days, which is thought to be caused by the progression of ossification from the spheroid's center. Moreover, the shape of the spheroid fully recovered after compression for 1 minute, whereas the spheroid showed plastic deformation after compressing for more than 5 minutes. In order to evaluate the bone-likeness of the spheroids in detail, measurement of the local mechanical properties directly targeting the calcified areas inside the spheroid will be necessary in the future beyond the evaluation of the global mechanical properties conducted in this study.