OBJECTIVETo examine the expression of Osterix (Osx) mRNA and protein after application of mechanical force on human periodontal ligament cells (HPDLCs), and to investigate the role of Osx in orthodontic alveolar bone remodeling.

METHODSHPDLCs were isolated and cultured in vitro with explant method. Approximately 2.5 x 10(5) cells were seeded onto six-well cell culture plates and then were exposed to centrifugal force for 1, 2, 4, 6, 8 or 12 h at 631 r x min(-1). The expression of Osx mRNA and protein was measured by reverse transcription-polymerase chain raction (RT-PCR) and Western blot respectively. Immunofluorescence assay was used to detect the expression and subcellular At the initial time point, Osx mRNA had a weak exlocalization of Osx protein by green fluorescence.

RESULTSpression and protein was not detected. Under the mechanical stimulation, both mRNA and protein levels of Osx were upregulated in a time-dependent manner. Furthermore, Osx protein was translocated gradually from the cytosol into the cell nuclei.

CONCLUSIONThe expression and activation of Osx were enhanced by mechanical stress in HPDLCs, which indicates that Osx may play an important role in HPDLCs osteogenic differentiation and periodontal tissue remodeling induced by mechanical stress.