Mechanical Loading Regulates PDL Cell Mineralization

The cultured PDL cells were subjected to mechanical tensile loading in vitro using the Flexcell® 5000 tension system (Flexcell, Burlington, North Carolina, USA). In brief, cells were seeded onto flexible-bottomed BioFlex® (Flexcell) 6-well culture plates at a density of 2 × 10⁵ cells/well and cultured until they reached 80% confluence. After a 12-hour period of serum starvation, the cells were subjected to static waves of 12% equibiaxial tensile strain using a computer-controlled vacuum stretch apparatus (17 (link)). PDL cells in the control group were cultured under the same conditions in the absence of tensile loading. Cells were subjected to tensile loading for 12 hours or 3 days for qPCR and western blotting, respectively, and continued to culture for 10 days prior to Alizarin Red S staining (ARS).