Effect of Fluid Shear Stress on Apoptosis and Osteogenesis of Mesenchymal Stem Cells

Abstract Mechanical cues, including fluid shear stress (FSS) of interstitial flow within bone cavities, induce osteogenic differentiation of mesenchymal stem cells (MSCs). However, whether FSS leads to the apoptosis of MSCs and its relation with osteogenic differentiation are still unclear. In this study, the effect of FSS on apoptosis and osteogenesis of MSCs is investigated. FSS is applied intermittently to MSCs through a cone-plate flow chamber system for 3 d. And results show that FSS inhibits the apoptosis of MSCs. Compared with static culture group, FSS promotes osteogenesis, as shown by the expression of three osteogenic differentiation markers, namely, alkaline phosphatase (ALP), osteocalcin (OCN), and collagen I (COL I). Double staining of individual cells shows that the relationship of apoptosis and osteogenic differentiation of MSCs is mutually exclusive. YAP may mediate the FSS-inhibiting apoptosis of MSCs. The results will further elucidate the mechanism of mechanical stimulation-induced bone remodeling.