Rankl And Opg In Tooth Movement In Rats Root Resorption And Early Repair In The Expression Study

Part one Expression of OPG and RANKL in the process of orthodontic induced root resorption in rats.Objective To investigate the role of OPG and RANKL in induction of osteoclasts during the process of orthodontic induced tooth root resorption of rats.Methods The process of orthodontic induced tooth resorption of upper molars was performed in 39 Wistar rats(6-8 weeks).The rats were divided into control group(3 rats)and experimental group(6 rats each group).The model of orthodontic induced tooth resorption was peformed in the experimental group.The animals were sacrisfied in 0d,1d,3d,5d, 7d,10d,and 14d respectively.The morphologic change was observed. The expression of OPG and RANKL protein at the compression sites was detected by immunohistochemical staining technique.Furthermore,we observed the TRAP positive cells in this process.Results After 7 days of the establish of orthodontic induced root resorption model,the obvious root resorption was observed,and absorption lacunas were detected at the edge of alveolar bone and in the cementum.The TRAP positive mononucleated osteoclast were increased in 1d,3d,5d and 7d;while the TRAP positive multinucleated osteoclast were increased in 3d,5d,7d and 10d.Immunohistochemical staining revealed that amount of OPG protein was increased in 3d,5d,7d,10d; that amount of RANKL protein was increased in 5d,7d,10d.Conclusion It indicates that the osteoclast plays key role in the process of orthodontic induced root resorption,and the amount and location of osteoclasts changed with time.The expression of OPG,RANKL is related to this process.Part two Expression of OPG and RANKL in the repair process of orthodontic induced root resorption in rats.Objective To investigate the role of OPG and RANKL in induction of osteoclasts during the repair process of tooth root resorption.Methods The repair of orthodontic induced tooth resorption of upper molars was performed in Wistar rats.The expression of OPG protein at the compression sites was detected by immunohistochemical staining technique.Furthermore,we observed the TRAP positive cells in this process.Results The TRAP positive cells were decreased from the first day after removing the force,and the amount of the TRAP positive cells was almost the same as normal after 7 days.Immunohistochemical staining revealed that amount of OPG,RANKL protein was decreased from the first day after removing the force,and from the third day on,the amount of the OPG,RANKL protein was almost the same as normal.Conclusion It indicates that the root of rats stopped resorption immediately after the the removal of the force,and started to repair after 1-3 days.The expression of OPG,RANKL is related to this process.