Wnt5a Stimulates the Bone Formation in Tension Side during Orthodontic Tooth Movement

Abstract

　In this study, we first investigated the expression of wnt5a in tension sites during experimental tooth movement in rats in vivo. We then assessed the effects of wnt5a on the expression of　bone marker from human periodontal ligament (hPDL) cells.
　Twelve male 6-week old Wistar rats were subjected to an orthodontic force of 10g in order to induce the mesial tipping movement of the upper first molars for 7 days. The expression levels of wnt5a proteins in the alveolar bone were determined using an immunohistochemical analysis. Furthermore, the effects of wnt5a on the gene expressions of alkaline phosphatase (ALP) and type I collagen (COL1) were investigated using hPDL cells in vitro.
　Under the conditions ofexperimental tooth movement in vivo, the immunoreactivity for wnt5a was detected in the tension side on day 7 in the PDL tissue ofrats subjected to the orthodontic force (10g). In the in vitro study, wnt5a treatment increased the gene expression ofALP and COL1 from the hPDL cells in a time-dependent manner.
　These results suggest that the wnt5a stimulates the alveolar bone formation in the tension side during orthodontic tooth movement.