Fiber system degradation, and periostin and connective tissue growth factor level reduction, in the periodontal ligament of teeth in the absence of masticatory load
Fiber system degradation, and periostin and connective tissue growth factor level reduction, in the periodontal ligament of teeth in the absence of masticatory load
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DOI：
10.1111/j.1600-0765.2011.01351.x
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发表时间：
2011-10-01
影响因子：
3.5
通讯作者：
Nakamura, Y.
中科院分区：
文献类型：
--
作者：
Choi, J. W.;Arai, C.;Nakamura, Y.
背景和目的：牙周膜（PDL），这是介于牙槽骨和牙根，支持牙齿对抗机械应力。骨膜蛋白和结缔组织生长因子（CTGF）可能在机械应力下维持PDL纤维完整性中起重要作用。然而，这种关系尚未在蛋白质和基因水平上进行研究。因此，本研究的目的是评估牙周膜纤维系统，没有咀嚼负荷，以确定在牙周膜的结构变化，在没有机械stress.Material和方法：本研究包括45只Wistar雄性大鼠（12周龄），其右上第一磨牙从咬合24小时，72小时，7天或21天。结果：牙周膜间隙宽度明显缩小，牙周膜内骨膜蛋白和结缔组织生长因子基因和蛋白表达水平明显升高。在组织学上，观察到PDL纤维的纤维数量和变薄的初始减少，随后PDL纤维的排列紊乱及其与牙槽骨的附着;最后，PDL纤维失去了它们的网状结构。实时荧光定量RT-PCR结果显示，骨膜蛋白和CTGF mRNA水平的急剧下调，分别在24和72小时，在整个实验中持续。免疫组化分析显示，骨膜蛋白定位于细胞成分和细胞外基质，而CTGF仅定位于细胞成分。结论：在没有机械应力的情况下，牙周膜纤维系统发生降解伴随着牙周膜中骨膜蛋白和CTGF水平的降低。
Background and Objective: The periodontal ligament (PDL), which is interposed between the alveolar bone and roots, supports teeth against mechanical stress. Periostin and connective tissue growth factor (CTGF) might play essential roles in maintaining PDL fiber integrity under mechanical stress. However, this relationship has not been studied at the protein and gene levels. Therefore, the aim of this study was to assess the PDL fiber system without masticatory load to determine the structural changes in the PDL in the absence of mechanical stress.Material and Methods: The study included 45 Wistar male rats (12 wk of age) whose upper-right first molars were relieved from occlusion for 24 h, 72 h, 7 d or 21 d. The PDL was examined histologically, and changes in the gene and protein levels of periostin and CTGF were investigated.Results: The PDL space width was reduced significantly. Histologically, an initial reduction in the fiber number and thinning of PDL fibers were observed, followed by disarrangement of the PDL fibers and their attachments to the alveolar bone; finally, the PDL fibers lost their meshwork structure. Real-time RT-PCR results revealed sharp down-regulation of the periostin and CTGF mRNA levels at 24 and 72 h, respectively, which continued throughout the experiment. Immunohistochemical analysis revealed that periostin localized to both the cellular elements and the extracellular matrix, whereas CTGF localized only to the cellular elements. Periostin and CTGF immunoreactivities became very weak without masticatory load.Conclusion: In the absence of mechanical stress, the PDL fiber system undergoes degradation concomitantly with a reduction in the periostin and CTGF levels in the PDL.