Responses of osteoblasts under varied tensile stress types induced by stretching basement materials

Osteoblasts are mechanosensitive cells. Tensile stress with different conditions, including loading time, frequency, magnitude, etc. would cause varied responses in osteoblasts. However, it was not clarified that the effect of the loading types on the osteoblasts. In this study, we focused on the effect of varied tensile stress types on osteoblasts, including isotropic stretch, biaxial stretch, and uniaxial stretch with the negative ratio of transverse strain to axial strain (NR) -1, 0, and 0.2 respectively. Cell proliferation was determined to be most efficient when stimulated by 6% strain at a frequency of 1 Hz and a negative value of 0 for 1 h/day. The varied strain resulted in a thickening of the F-actin cytoskeleton and a thinning of the nucleus. Nuclear flattening caused Yes-associated protein (YAP) to be transported to the nucleus. It was suggested that the influence of loading types on the mechanobiology responses must be noticed. The mechanism of cell mechanical sensitivity under varied loading types was explored, which would provide good suggestions for designing microstructures to control deformation patterns in bone tissue engineering.