Orthodontic force influences the activity of osteoclasts in alveolar bone remodeling by regulating EphB4/ephrinB2 expression

EphB4/ephrinB2 signaling plays an important role in bone remodeling, but the role of orthodontic force regulated EphB4/ephrinB2 expression in influencing osteoclastogenesis in alveolar bone remodeling remains to be studied. A rat alveolar bone remodeling model was induced by orthodontic force, and we observed microstructural changes in the alveolar bone using Micro CT and hematoxylin-eosin (HE) staining methods. EphrinB2 expression localization was detected by immunofluorescence. EphrinB2 and EphB4 protein expressions were tested by western blot. EphrinB2, EphB4, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa B ligand (RANKL) mRNA levels were determined by real-time PCR. After placing the orthodontic device, the rats did not change their drinking and eating habits, and the orthodontic side gingival tissue and the surrounding mucosa were slightly congested. Micro-CT (HECT) and HE staining showed large and multinucleated osteoclasts near the orthotopically absorptive lacunae. Immunofluorescence exhibited strong positive ephrinB2 expression in the orthodontic pressure zone. Western blot and real-time PCR demonstrated EphrinB2 upregulation and EphB4 downregulation in the pressure zone. OPG expression was reduced, but the RANKL level was elevated on the orthodontic side. In the alveolar bone remodeling model, orthodontic force can regulate EphB4/ephrinB2 expression and affect the activity of osteoclasts. It provided a theoretical basis for the mechanism of stress zone remodeling during orthodontic tooth movement, and helped to discover substances that can regulate the activity of osteoblasts and osteoclasts, thereby regulating bone remodeling.