Differential responsiveness against mechanical stress between osteoblastic cells and periodontal ligament cells

Using the human osteosarcoma-derived osteoblastic cell line, HOS cells, and the human periodontal ligament-derived fibroblast-like cells (Periodontal ligament cells; PDL cells), we examined the responsiveness against mechanical stress (continuously applied compressive force) in HOS and PDL cellsin vitro. SDS-PAGE revealed that loading of mechanical stress (10 g/cm²) promoted intracellular protein production (approx. 30–35 kDa, 40kDa, 55kDa, 65–70kDa) in HOS cells, which are different sizes from those in PDL cells reported previously. Mechanical stress also enhanced heat shock protein (HSP) production in HOS cells and PDL cells: however, the responsiveness was different between HOS cells and PDL cells. In PDL cells, mechanical stress enhanced HSP 60 production more efficiently, in contrast that HSP 70 production was promoted more efficiently in HOS cells. These data suggest that differential responsiveness against mechanical stress between osteoblasts and PDL cells might have important role during orthodontic tooth movement.