犬切牙压低移动过程中牙周组织骨保护素/核因子κB受体活化因子配体的表达

Expression of osteoprotegerin/receptor activator of nuclear factor kappa B ligand in the periodontal tissue incident to incisors intrusion on dog

背景:骨保护素及核因子κB受体活化因子配体是调控破骨细胞生成和活化的关键因子,机械力可影响牙周膜细胞和成骨细胞骨保护素及核因子κB受体活化因子配体的表达。目的:观察犬切牙压低移动过程中牙周组织中骨保护素/核因子κB受体活化因子配体的表达。方法:采用微型种植体作为支抗,将犬切牙分别施加牵引力1,2,4,12周,并设置对照组进行比较。牵引后切取犬切牙连同牙龈及牙槽骨组织块,制作组织切片进行骨保护素及核因子κB受体活化因子配体免疫组织化学染色,用Image-Proplus软件半定量分析图像平均吸光度值。结果与结论:与对照组相比,核因子κB受体活化因子配体和骨保护素分别在在施加牵引力1和2周表达最显著,其平均吸光度值在施加牵引力1和2周时可达到峰值(P<0.05),随后逐渐下降,施加牵引力12周恢复至对照组水平。结果证实,正畸牙压低移动过程中核因子κB受体活化因子配体及骨保护素的表达变化规律与骨改建过程一致,骨保护素/核因子κB受体活化因子配体系统是牙周组织改建的重要调节因素。

BACKGROUND：Osteoprotegerin （OPG） and receptor activator of nuclear factor-κB ligand （RANKL） play important role in osteoclast formation and activation.The expression of OPG/RANKL in the periodontal tissues during orthodontic tooth movement is to be studied.OBJECTIVE：To observe the expression of OPG/RANKL in the periodontal tissue incident to incisors intrusion on dogs.METHODS：Nine healthy hybrid dogs were selected and randomly divided into 5 groups.The control group contained 1 dog with no force loaded;Applied force for 1 week,2 weeks,4 weeks and 12 weeks （4 weeks after activation,then retention for 8 weeks） were the four experimental groups,which were contained 2 dogs respectively.The dog of the control group was killed immediately.Dogs of other groups were killed after the force was applied 1 week,2 weeks,4 weeks and 12 weeks.Then the gums and alveolar bone tissues were completely cut to make the specimens.An immunohistochemical staining technique was utilized to detect the expression of OPG/RANKL.The average optical density images were semi-quantitative analyzed by Image-Proplus software to reflect the expression levels of RANKL and OPG in the periodontal tissues in each group.RESULTS AND CONCLUSIONS：The expression of RANKL in the no force loaded group （the control group） in the periodontal ligament tissues showed weak positive.The expression of RANKL was the most significant after applying force for 1 week.The expression still showed positive,but became weak after applying force for 2 weeks.The expression was decreased significantly after applying force for 4 weeks.The expression was close to the control group after activation 4 weeks then retention for 8 weeks.The average optical density level was measured by image analysis and demonstrated that it reached peak in the 1 week （P〈0.05）,then declined gradually.There were significant differences compared with the control group （P〈0.05）.Expression of OPG in the no force loaded group （the control group） in the periodontal ligament tissues showed weak positive.The expression of OPG was increased significantly after applying force for 1 week.And in 2 weeks,the expression reached peak.Then the expression was decreased after applying force for 4 weeks.The positive expression regained to the level of the control group after activation 4 weeks then retention for 8 weeks.The average optical density value reached peak in the 2 weeks and it was significant stronger than the control group （P〈0.05）.The results confirm that the expression change characters of RANKL and OPG are the same as the reconstruction of alveolar bone.RANKL and OPG participate in the reconstruction of periodontal tissues.