Résumé
Objective To study the remodeling of alveolar bone and change in expression of forkhead box O1 (FOXO1) during orthodontic tooth movement (OTM) in rat, so as to preliminarily investigate the role of FOXO1 in alveolar bone remodeling induced by orthodontic force. Methods The rat OTM models were established and the left maxillary 1st molars were moved with force of 50 g. The rats were executed on the 1st, 3rd and 7th day of OTM, respectively. HE staining and immunohistochemical staining were used to observe the remodeling of alveolar bone in the inter-radicular region of the 1st molars and expression of FOXO1 at different time points during OTM. Results The 1st molars were constantly moved mesially under orthodontic force. There were more osteoclasts in the alveolar bone of OTM group than that in non-OTM group, and the osteoclasts on the 3rd day of OTM showed the highest activity. The number of active osteoblasts gradually increased in the inter-radicular region of alveolar bone under orthodontic force, with the enhanced osteoblast activity. Expression of FOXO1 in OTM group was elevated compared with non-OTM group. Most osteoblasts in alveolar bone during OTM were FOXO1 positive, and the expression of FOXO1 was gradually increased with the number of osteoblasts increasing. Conclusions Orthodontic force induces bone remodeling of alveolar bone in the inter-radicular region during OTM, and the change in FOXO1 expression may be related to alveolar bone remodeling during OTM.
Résumé
The purpose was to evaluate the influence of a NSAID, Diclofenac Sodium (DFS) on the tissue reaction related to orthodontic tooth movement (OTM). Methods: 27 adult male wistar rats were divided into 3 Groups of 9 each. Orthodontic closed coil spring was placed between rat incisor and molar to produce a 50 gm of force. The experimental Groups1 and 2 received orthodontic force and either DFS of 0.0025mg/0.05ml or 0.05ml of saline, Group 3 received only orthodontic force and served as a control group. At the end of day 5, 10 and 15 the animals were sacrificed and histological examination was performed. Results: Student’s t test showed a statistically significant difference between the control Groups and experimental Groups. Group 1 showed a statistically significant reduction in osteoclastic cell count at day 5, 10 and15 when compared to Group 2 and Group 3. Conclusion: The results indicate that the Diclofenac Sodium even at low concentration level diminishes the number of osteoclasts probably by inhibiting the secretion of prostaglandins there by reducing the OTM.
Résumé
In recent years, great development has been made in cytomechanics in orthodontic tooth movement（OTM）.The essential role of periodontal ligament in OTM has been widely accepted. The in vitro models have become an important way to reveal the biological mechanism in OTM,largely based on periodontal ligament cells(PDLCs), as well as other cells, including bone marrow mesenchymal stem cells, osteoblast, cementoblast and myoblast.The in vitro models have been renovated from the traditional ways stressing the 2D cultured cells by deformation of the bottom,gravity, hydrostatic pressure or centrifugation, to the establishment of various novel models loading mechanical stimulation on cells 3D cultured in bioscaffolds. The molecular expression involved in the osteoblastic differentiation and osteoclastogenesis induction in the bone remodeling cycle has drawn great attention, and will continue to be a focus of study. Furthermore, with the identification of periodontal ligament stem cells(PDLSCs), the cytomechanics involved in OTM and periodontitis, will undoubtedly be a promising new direction.