Expression Of FoxO1 And Runx2 In Periodontal Tissue Remolding During Orthodontic Tooth Movement With The Relationship Between The Two Facts

Nowadays,more and more patients with dental or facial defects seek orthodontic treatment.Therefore,it is significant to explore the biological role and molecular mechanism of orthodontic tooth movement.OTM is a complex biological process,we can study its dynamic changes by detecting its growth factors,active enzymes,cytokines,proteoglycans and so on.The FoxO protein group is a group of wings with double helix DNA,which plays an important role in many biological processes,including apoptosis,glycometabolism,oxidative stress and stress signaling pathway.It is suggested that down-regulation of FoxO1 can promote the proliferation and tumorigenesis of endometrium,prostate and thymus,so FoxO1 has become the main target of tumor prevention and treatment.At the same time,FOXO family is involved in redox equilibrium and osteogenic differentiation.Down-regulation of FoxO1 in osteoblasts can lead to the decrease of osteoblasts and the decrease of bone formation.Moreover,because FoxO1can promote the maintenance and differentiation of osteoblasts at the same time,it can induce osteoclasts.Therefore,it is significant for the balance of bone.Recently,it shows that the silencing of FoxO1 may decrease the expression of Runx2 and affect the formation of bone.However,another scholars found that FoxO1 is a negative regulator of Runx2.There are few reports on the role of Fox O1 and Runx2 and their relationship in orthodontic tooth movement.The purpose of this study was to study the role of FoxO1and Runx2 in periodontal tissues during orthodontic tooth movement and the effect of silencing FoxO1 on the expression of Runx2 in periodontal ligament cells,and then explore their relationship in periodontal tissue remodeling.The experiment was divided into two parts:Part 1:Expression of FoxO1and Runx2 in periodontal tissue during orthodontic movement of teeth in rats.Objective:To investigate the expression of FoxO1 and Runx2 in periodontal tissue?and their effect?during?orthodontic?teeth?movement?OTM?in rats.Methods:Forty 8-weeks old male Sprague-Dawley?SD?rats were used to establish animal models of orthodontic?teeth?movement and divided into5 groups randomly.The right side of jaws of each rat was set as experimrntal side,and the left side as control side.At 1 d,3 d,5 d,7 d and 14 d day after orthodontic treatment,the rats were sacrificed and the maxillary bone containing the first molar was dissected.Hematoxylin-eosin staining and immunohistochemical staining were used to detect the morphological changes,the expression of FoxO1 and Runx2 of the periodontal tissue at different points was detected and computer image analyses was used to evaluate the expression of FoxO1 and Runx2 in the periodontal tissues of the rats.The differences were analyzed by using SPSS19.0 software package.Results:The expression of FoxO1 in periodontal ligament is mainly in osteoblasts and cementoblasts.And the expression of Runx2 is mainly in osteoblasts,fibroblasts and cementoblasts.In the experimental group,the expressions of FoxO1 and Runx2 in the periodontal tissues of rats increased significantly,reached the peak within 3-5 days,then decreased,and there was no significant difference between the experimental group and the control group on the 14th day?P>0.05?.The rest of the time expression and control group were statistically significant?P<0.05?.Conclusion:FoxO1 and Runx2 play a role in the reconstruction of periodontal tissue during orthodontic movement of tooth,and they are mainly involved in the process of osteoblast formation and bone formation.Part 2:Effect of FoxO1siRNA on the expression of Runx2 in human periodontal ligament cells.Objective:To investigate the effect of FoxO1 siRNA on the expression of Runx2 in human periodontal ligament cells?hPDLCs?.Methods:The hPDLSCs were isolated by enzyme digestion,and cells of 4 to 6 passage were used in the experiment.They were respectively transfected into cells by Lipofectamine^TM 2000.These three groups of cells were set as siRNA-NC group?negative control group?,blank control group?untransfected group?and FoxO1siRNA group?experimental group?.The expression of FoxO1 were identifled by RT-PCR.ALP and ARS staining were used to detect the osteogenic differentiation of hPDLCs after siRNA interference.The expression of Runx2 was detected by RT-PCR and Western blot.The results were analyzed by SPSS 19.0 software.Results:Expression of FoxO1 mRNA of siRNA group was down-regulated for transfection?P<0.05?.The results of ALP and ARS staining showed that the siRNA group significantly decreased ALP activity and calcium nodule formation.Expression of Runx2 mRNA and protein of FoxO1siRNA group was down-regulated for transfection?P<0.05?.Conclusion:FoxO1 siRNA inhibits the expression of Runx2 in hPDLCs.