增龄因素对鼠正畸牙牙周组织骨保护素及其配体表达的影响

目的:比较幼年鼠和成年鼠在正畸牙移动中牙周组织骨保护素(OPG)及其配体(OPGL)表达的不同比值,探讨增龄因素对正畸骨改建影响的分子机制。方法:制备大鼠正畸牙齿移动模型,于牙齿移动1d、3d、5d、7d、10d、14d及14d后去除正畸力1周后取材,免疫组化检测牙周组织OPG和OPGL的表达。结果:①.牙齿移动3d时,幼年鼠压力侧OPGL的表达明显增强;而成年鼠此时OPGL的表达没有幼年鼠明显。②.牙齿移动5d和7d时,幼年鼠和成年鼠OPGL的表达均成强阳性,破骨细胞多。③.牙齿移动10d、14d时,幼年鼠和成年鼠OPGL的表达逐渐减弱。④.14d时去除正畸力至21d时发现幼年鼠和成年鼠OPGL均已成弱阳性表达,幼年鼠可见部分成骨细胞。结论:在正畸力的作用下,OPGL与OPG的表达比值与年龄关系密切,增龄因素引起的牙周组织内OPGL/OPG表达变化可能是导致成年正畸特点的分子机制之一。

Age effect on OPG and OPGL expression in periodontal ligament cells during orthodontic tooth movement

Objective:To compare the difference of OPG and OPGL expression in rat periodontal ligament(PDL)cells during orthodontic tooth movement between young and aged rats and to explore the possible mechanism of the age-related difference in orthodontic bone remodeling.Method:The orthodontic tooth movement of right upper molars was performed in four-week(juvenile)and 24-week(adult)SD rats.The expression of OPG and OPGL protein was detected by immunohistochemical staining technique at 1,3,5,7,10,14d after applying orthodontic force and 21d(removing applied orthodontic force at 14d).Result:On day 3 after tooth movement,OPGL expression positive cells on the pressure side of the young rats were much stronger than that of aged ones .On day 5 and 7 after tooth movement,the expression of OPGL was remarkably increased in both young and aged rats.At the same time,a large amount of osteoclasts appeared.On day 10 and 14 after tooth movement,the expression of OPGL decreased gradually.On day 21(applied orthodontic force was removed at 14d),the expression of OPGL was weak for all rats.There were several osteoblasts located in the related bone resorbing lacunae of young rat alveolar bones.Conclusion:The ratio between OPGL and OPG was closely related with age under orthodontic force .OPGL/OPG plays an important role in alveolar bone remodeling.The transformation of the expression of OPGL/OPG in periodontal tissues by aging factors may be the molecular mechanism,which results in adult orthodontic characteristics.