Expression of /sclerostin in compressed periodontal ligament cells.

BACKGROUND/PURPOSE: Bone resorption and inhibition of bone formation occur on the compressed side during orthodontic tooth movement. Bone formation inhibitory factors such as sclerostin (encoded by ) are secreted on the compressed side by periodontal ligament (PDL) cells. PDL cells control bone metabolism, and compressed PDL cells inhibit bone formation during orthodontic tooth movement. The aim of this study was to identify the inhibitory factors of bone formation in PDL cells.

MATERIALS AND METHODS

Changes in expression and subsequent protein release from human PDL (hPDL) cells were assessed using the real-time polymerase chain reaction (PCR), semiquantitative PCR, and immunofluorescence in hPDL cells subjected to centrifugal force (40 and 90). To confirm the effects on bone formation, human alveolar bone-derived osteoblasts (hOBs) were grown with the addition of sclerostin peptide. , a compressive force was applied using the Waldo method in rats, and the distribution of sclerostin in PDL tissues was examined by immunohistochemistry.

RESULTS

expression was downregulated by centrifugation at 90 for 24 hours but upregulated by centrifugation at 40 based on real-time PCR, as was confirmed by immunofluorescence staining. The addition of sclerostin peptide significantly decreased the mineralized area in hOBs. However, slightly weakly sclerostin-positive PDL cells were observed on the compressed side .

CONCLUSION

These results indicate that PDL cells subjected to light compressive force exhibit increased expression of /sclerostin, which inhibits bone formation on the compressed side during orthodontic tooth movement.