Osteoclastogenesis accompanying early osteoblastic differentiation of BMSCs promoted by mechanical stretch

Abstract

Abstract. Mechanical stress plays a crucial role in bone formation and absorption. In previous studies, we verified the osteoblastogenesis of bone mesenchymal stem cells (BMSCs) affected by intermittent traction stretch. However, little is known about the osteoclastogenesis process under mechanical stimulation and its underlying association with osteoblastogenesis. In the present study, we investigated the osteoclastogenesis of BMSCs under this special mechanical stress. BMSCs were subjected to 10% elongation for 1-7 days using a Flexcell Strain Unit and then the mRNA levels of osteoclastic genes were examined. The results indicated time-dependent varying of mRNA levels of the receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in BMSCs at different stretching time points. The ratio of RANKL/OPG increased at the early stage of mechanical stimulation (5 days) and decreased to a low level at a later stage (7 days). Findings of this study may help to understand the correlations between osteoblastogenesis and osteoclasteogenesis when mechanical stretch induces the osteoblastic differentiation of BMSCs.

Uniaxial Cyclic Tensile Stretching at 8% Strain Exclusively Promotes Tenogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stromal Cells

“…Thus, it is not unexpected that uniaxial cyclic stretch is believed to be of paramount importance in the development of functional musculoskeletal tissues [50] especially for the differentiation of MSCs into tendon/ligament fibroblasts. One aspect that needs to be considered is that the differences observed between our study and that of previous reports [51–53] may have been related to the Flexcell system used in their studies. In contrast to the Strex machine used in our study, this device employs a suction mechanism at the centre of the elastomeric cell culture surface to create the stretching effect.…”

“…It needs to be reminded however that these changes may be better applied for static cultures and probably not applicable to our stretching cultures [65, 66]. Results from other studies seem to suggest that this is the case [53, 67, 68]. Notwithstanding these limitations, the findings of the present study are still valid and useful owing to the robust study design employed.…”

Mechanical stretch and chronotherapeutic techniques for progenitor cell transplantation and biomaterials

“…The authors also found that this long term application of strain reduced the proliferative capacity of MSCs, supporting the notion that although short-term strains may increase proliferation, long-term strains do not appear to [7]. It has also been shown that both osteoblastogenesis and osteoclastogenesis are influenced by mechanical stimulation, showing how far reaching the effects of mechanical load are in bone formation and maintenance [30, 31]. …”

Three-Dimensional Mechanical Microenvironment Rescued the Decline of Osteogenic Differentiation of Old Human Jaw Bone Marrow Mesenchymal Stem Cells

“…A series of signaling pathways, ion channels, and connections between the bone matrix and cytoskeleton were found involved in the cellular response to mechanical stress . Traditional cell culture stressing models include four-point bending stressing, − FX-4000T , and FX-5000T, , but 2D culture and stressing methods cannot accurately simulate the 3D environment in which cells are placed in vivo, and it is questionable whether the reliability of the experimental results is representative of the stressing of cells in the 3D environment. In vivo, hJBMSCs are in a 3D mechanical microenvironment surrounded by an extracellular matrix.…”