Reaserch On Effect Of NF-?B Signal Way On Orthodontic Periodontal Tissue Remolding

Since Angle created the edgewise appliances in the early 20 th century, development of orthodontic has been advancing by leaps and bounds, subsequently, the invention of straight-wise appliances brought orthodontic up to a high-class level. Recently, lingual braces and invisible appliances are more and more popular and widely recepted for the reason they are more comfortable and elegant. However, though treatment methods may vary, the principle remains the same. Any kind of appliance is based on the right cognizance and application of biological mechanism of tooth movement. With the gradual maturation of orthodontic technique and increasing popularity of orthodontic treatment, requirement for correction is more and more strict. How to complete a clinical case in a way which is more effective, safe, and high level emerges as a challenge for orthodontists. In order to conquer the puzzle, biological mechanism of tooth movement should be made certain as a key element. The biological mechanism of tooth movement is the theory of periodontal tissue remolding in the present of mechanical stress, whose emphases lie in bone remolding. So, explaining bone remolding mechanism under stress not only contributes to seek for more scientific and rational treatment means, but also provides new experimental evidence for prophylaxis and treatment of systemic skeletal disease.Researchers have achieved much in bone remolding, however, some key problems remain to be solved. For example, bone resorption and bone formation constitute bone remolding, but the coupling mechanism of which is still unclear. Recent years has demonstrated that OPG/RANKL/RANK signal system is essential for promoting osteoclast differentiation and maturation, and Eph B4/ephrinB2 bi-direction signal transduction mechanism plays a key role in regulating osteoblast differentiation and bone formation. However, relationship between the two signal paths is rarely reported. So, are there some signal routings which is able to connect the two signal ways with each other and therefore compose a coupling mechanism of bone resorption and formation? Given what we have found previously in this field and that a good deal of research achievements has been established, we speculate that NF-?B signal way which is widely involved in physiology and pathology may be a connection and regulative centre between or among those signal ways.According to this hypothesis, by building animal models, we make a preliminary discussion about the relationships between NF-?B signal way and OPG/RANKL/RANK signal system or EphB4/ephrinB2 bi-direction signal transduction mechanism.Part? Influence of NF-?B signal way inhibitor BAY 11-7082 on rat orthodontic tooth movementAim: Observe influence of NF-?B signal way inhibitor BAY 11-7082 on rat orthodontic tooth movement.Methods: 60 rats were divided in 3 groups. Control group, orthodontic tooth movement group(OTM), OTM+ BAY 11-7082 group. Control group were subjected to no precessing, OTM group were built on OTM model, and OTM+ BAY 11-7082 group were additional experienced local BAY 11-7082 injection. Investigate the periodontal tissue biological and morphology changes of experimental tooth mesio-pressure area. Collect quantitative indicators and make statistical analysis.Results: Compared with OTM group, periodontal ligament width changes of mesio-pressure area decreased, and so did the amount of osteoclast formation, tooth movement distance and bone volume fraction(BVF) droop in OTM+ BAY 11-7082 group. The difference was significant(P<0.05).Conclusion: Inhibition of NF-?B signal way weakened periodontal tissue biological changes of mesio-pressure area in rat orthodontic tooth model, decreased osteoclast formation, hence impeded tooth movement.Part? The relationships between NF-?B signal way and OPG/RANKL/RANK signal system or EphB4/ephrinB2 bi-direction signal transduction mechanism in orthodontic periodontal ligament remoldingAim: Investigate relationships between NF-?B signal way and OPG/RANKL/RANK signal system or EphB4/ephrin B2 bi-direction signal transduction mechanism in orthodontic periodontal ligament remolding.Methods: Using IHC dyeing technique to detect expression of NF-?B p65, OPG, RANKL, EphB4, ephrinB2 in mesio-pressure area periodontal tissue of the three samples.Results: Compared with OTM group, expression of NF-?B p65, OPG, RANKL, ephrinB2 in mesio-pressure area periodontal tissue decreased in OTM+ BAY 11-7082 group, while that of EphB4 increased. The difference was significant(P<0.05).Conclusion: Inhibition of NF-?B signal way blocked up NF-?B signal way, indicating that activation of NF-?B signal way participate in regulation of osteoclast formation in in mesio-pressure area periodontal tissue; the blockade of NF-?B signal way decreased expression of OPG, RANKL, ephrinB2 in mesio-pressure area periodontal tissue and enhanced expression of EphB4, indicating that NF-?B signal way is closely related to OPG/RANKL/RANK signal system and EphB4/ephrin B2 bi-direction signal transduction mechanism, probably play a core role in coupling mechanism of bone remolding.