Effects of cyclic longitudinal mechanical strain and dexamethasone on osteogenic differentiation of human bone marrow stromal cells

Abstract

The aim of the study was to investigate the effect of cyclic mechanical strain on differentiation markers in the presence or absence of dexamethasone. Human bone marrow stromal cells (BMSC) from seven donors (32.5±6.2 years) were cultivated with (D+) or without (D-) dexamethasone. A cyclic mechanical strain with an elongation of 2% (D+2; D-2) or 8% (D+8; D-8) was applied for three days with a stimulation time of three times two hours each day. Levels of alkaline phosphatase (ALP) and osteocalcin (OC) were compared after time intervals of four and seven days. mRNA expression of Collagen I, III and Cbfa1 was investigated after one, four, and seven days. ALP levels were significantly increased in the D+8 group after four and seven days (147.1±6.3%; p<0.05 and 168.6±6,5%; p<0.03) and in the D-8 group after 7 days (197.4±10.4; p<0.04). Cyclic strain had a significant influence on ALP-secretion (F=7.5; p<0.01). In the D-8 group there was a significant increase in OC secretion after 4 days (140.9±12.5%; p<0.05).; p<0.01). The effect of stretching was significantly stronger than that of dexamethasone (F=17.2 vs. 1.8). Collagen I (Col I) expression was upregulated in D+8 cultures after 4 days (215.0±53.3 p<0.04) and after seven days (166.7±55.7; p<0.04). Collagen III (Col III) expression was upregulated in D+2 and D+8 cultures after 4 days (200.7±16.3 and 185.9±12.7; p<0.04) and after seven days (154.4±10.1 and 118.8±16.4; p<0.04). There was a significant increase of Cbfa1 expression in D+8 cultures at all investigated time intervals (day 1: 105.5±3.7%; day 4: 104.7±3.0%; day 7: 104.4±2.1%; p<0.03). Stretching (F=20.0; p<0.01) was a stronger contributor to Cbfa-1 expression than dexamethasone (F=12.1; p<0.01) Cyclical mechanical stimulation with 8% elongation increases ALP and OC levels and upregulates Col I and III synthesis and Cbfa1 expression. In the short term, cyclical stretching is a stronger differentiation factor than dexamethasone. Cyclical stretching and dexamethasone both enhance the osteogenic commitment of hBMSC.

CD73/5’-ecto-nucleotidase acts as a regulatory factor in osteo-/chondrogenic differentiation of mechanically stimulated mesenchymal stromal cells

“…Hence, the response of MSCs to mechanical loading followed current models that suggest that compressive load supports chondrogenic MSC differentiation ( Table 2) (Campbell et al, 2006;Mauck et al, 2007;Pelaez et al, 2009). In contrast, osteogenic differentiation of MSCs was unaffected by cyclic compression (3D) adding weight to the notion that osteogenic differentiation requires a different mechanical stimulus, such as cyclic equibiaxial/uniaxial strain (2D) or four-point bending (Table 2) (David et al, 2007;Jagodzinski et al, 2004;Koike et al, 2005;Mauney et al, 2004). Little is known about the function of CD73 in MSCs thus far.…”

Gamma-Tocotrienol Stimulates the Proliferation, Differentiation, and Mineralization in Osteoblastic MC3T3-E1 Cells

“…ON is synthesized by cells of the osteoblastic lineage, and it also is a differentiation marker of bone cells [46]. Col I, an important component of the bone extracellular matrix, has been shown to be involved in the differentiation of the osteoblast phenotype [47]. LiCl is able to increase osteoblast differentiation [48]; thus it was used as a positive control.…”

Expression of proinflammatory cytokines by human mesenchymal stem cells in response to cyclic tensile strain

“…Stimulation of human mesenchymal stem cells (hMSCs) by tensile strain and osteogenic media conditions to induce osteogenic differentiation has been widely investigated (Simmons et al, 2003;Jagodzinski et al, 2004;Koike et al, 2005;Sumanasinghe et al, 2006). Many investigations have focused on determining appropriate strain levels (Simmons et al, 2003;Jagodzinski et al, 2004;Loboa et al, 2005;Koike et al, 2005;Sumanasinghe et al, 2006) and media supplements Jaiswal et al, 1997;Halvorsen et al, 2001) required to achieve osteogenesis of hMSCs.…”

“…Many investigations have focused on determining appropriate strain levels (Simmons et al, 2003;Jagodzinski et al, 2004;Loboa et al, 2005;Koike et al, 2005;Sumanasinghe et al, 2006) and media supplements Jaiswal et al, 1997;Halvorsen et al, 2001) required to achieve osteogenesis of hMSCs. Tensile strains of 10-12% have been shown to initiate intramembranous bone formation in rats (Loboa et al, 2004(Loboa et al, , 2005.…”