【摘要】 目的比较幼年鼠和成年鼠在正畸牙移动中牙周组织破骨细胞分化因子(RANKL)表达的不同,探讨增龄因素对正畸骨改建影响的分子机制。方法牵引不同年龄大鼠右上第一磨牙近中移动建立正畸牙齿移动模型,于牙齿移动1、3、5、7、10、14及14d后去除正畸力1周后取材,采用免疫组化方法检测牙周组织RANKL的表达。结果①牙齿移动3d时,幼年鼠压力侧RANKL的表达明显增强;而成年鼠此时RANKL的表达没有幼年鼠明显。②牙齿移动5和7d时,幼年鼠和成年鼠RANKL的表达均成强阳性,破骨细胞多。③牙齿移动10、14d时,幼年鼠和成年鼠RANKL的表达逐渐减弱。④14d时去除正畸力至21d时发现幼年鼠和成年鼠RANKL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,RANKL的表达与年龄关系密切,增龄因素引起的牙周组织内RANKL表达变化可能是导致成年正畸特点的分子机制之一。更多还原

【Abstract】 Objective To compare the difference of RANKL 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. Methods The orthodontic tooth movement of right upper molars was performed in four-week(juvenile)and 24-week(adult)SD rats. The expression of RANKL protein was detected by immunohistochemical staining technique at 1, 3, 5, 7, 10, 14 d after applying orthodontic force and 21 d(removing applied orthodontic force at 14 d).Results On day 3 after tooth movement, RANKL 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 RANKL 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 RANKL decreased gradually. On day 21 ( applied orthodontic force was removed at 14d), the expression of RAKNL was weak for all rats. There were several osteoblasts located in the related bone resorbing lacunae of young rat alveolar bones. Conclusion The expression of RANKL is closely related with age under orthodontic force . RANKL plays an important role in alveolar bone remodeling. The transformation of the expression of RANKL in periodontal tissues by aging factors may be the molecular mechanism, which results in adult orthodontic characteristics.更多还原