The Expression of ODFmRNA During Orthodontic Tooth Movement in Rats

Objective: To observe the change of ODF mRNA expression and distribution during experimental tooth movement in rats, learn about the relationship between ODF and osteoclast recruitment on orthodontic alveolar bone remodeling. Methods: Orthodontic appliance was placed between the maxillary right first molar and maxillary central incisors of adult SD rat. Established rat molar movement model. In situ hybridization analyses were performed at 1,3,5,7days after orthodontic force application . Results: The expression of ODF mRNA were weak in normal periodontium and localized mainly in cytoplasm of osteoblasts and only a few periodontal ligament fibroblasts near the alveolar bone surface, and most of periodontal ligament fibroblasts were ODF mRNA- negative responses. On day 3 after tooth movement, the expression of ODF mRNA was marked increased on the pressure side, localized in osteoblasts near the alveolar surface, periodontal ligament fibroblasts of perivascular areas on the alveolar side and osteoblasts in bone marrow cavity. The reaction were more intense on the cells on the alveolar side than on the dental root side. At the same time, a great deal of multinuclear osteoclasts appearanced on the surface of the alveolar bone. On the tension side, the expression and distribution pattern of ODF mRNA showed no significant change. Conclusion: ODF participate in orthodontic alveolar bone remodeling during tooth movement, it was clear that the localization of ODF mRNA expression was concordant with the appearance of osteoclasts. ODF play an important role in the formation and recruitment of osteoclasts during orthodontic tooth movement. This study was supported by national natural science foundation of China(30300393)