Response to light compressive force in human cementoblasts in vitro.

The objective of this study is to investigate the responses of human cementoblasts to light compressive force in vitro. A human cementoblast cell line (HCEM) was loaded for 12 h by mounting coverslips (0.25 gf/cm2 ). The coverslips were removed and the cells were cultured for up to 21 days. Cells without glass loading were used as controls. Cell growth, morphological changes, and the mRNA expression of RUNX2, ALP, WNT5A and SPON1 were investigated. No significant differences were observed in cell numbers between the compressed group and control group. Morphology of the compressed cells was slightly flattened on day 0; however, no indications of cell death were detected. Expression of differentiation markers including RUNX2, ALP and WNT5A was significantly lower in the compressed group (0.7, 0.75 and 0.75-fold respectively, P < 0.05) than in the control group on day 7. The expression levels of SPON1, a differentiation marker of cementoblasts, were higher on days 7 and 14 than on day 0, but were lower in the compressed group than in the control group (P < 0.01). These results suggest that light compressive force does not affect cell growth and morphology, but restrains higher expression of cementogenic differentiation markers in human cementoblasts in vitro.