Cementocyte alterations associated with experimentally induced cellular cementum apposition in Hyp mice.
Cementocyte alterations associated with experimentally induced cellular cementum apposition in Hyp mice.
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DOI：
10.1002/jper.21-0119
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发表时间：
2021-11
影响因子：
4.3
通讯作者：
Nociti Júnior FH
中科院分区：
文献类型：
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作者：
Lira Dos Santos EJ;Salmon CR;Chavez MB;de Almeida AB;Tan MH;Chu EY;Sallum EA;Casati MZ;Ruiz KGS;Kantovitz KR;Foster BL;Nociti Júnior FH
细胞牙骨质是覆盖在根尖牙根上的矿化组织，通过附着生长来维持牙齿的咬合位置。我们假设，居民牙骨质细胞将显示形态学变化，牙骨质附着，可能涉及的作用，牙骨质生物学。通过拔除上颌磨牙诱导下颌第一磨牙超萌（EIA），促进新牙骨质快速形成。在术后6天和/或21天（dpp）分析组织和细胞反应。高分辨率显微计算机断层扫描（micro-CT）和共聚焦激光扫描显微镜显示细胞牙骨质增加21 dpp。透射电子显微镜（TEM）显示，EIA下的牙骨质细胞比对照细胞大50%，由micro-CT检测到的较大孔径支持。EIA下的牙骨质细胞显示与活性增加一致的超微结构变化，包括细胞质和核大小增加。我们将EIA应用于Hyp突变小鼠，其中牙骨质细胞具有泡周低矿化缺陷，以测试在改变的机械反应环境中的细胞和组织反应。Hyp和WT磨牙显示出相似的超萌出，在21 dpp时，Hyp磨牙显示出28%的细胞牙骨质面积增加，而WT小鼠为22%。与对照组相比，Hyp牙骨质细胞的特征是边界清楚，分散的常染色质和一层厚的外周凝聚的异染色质，表明细胞活性。牙骨质标记物的免疫组化显示Hyp小鼠牙本质基质蛋白-1表达强烈，骨桥蛋白沉积异常。WT和Hyp牙骨质细胞均表达间隙连接蛋白，连接蛋白43。本研究为EIA模型和与新牙骨质形成相关的牙骨质细胞活性提供了新的见解。总的来说，我们证明了超萌后牙骨质细胞的形态学和超微结构的变化。
Cellular cementum, a mineralized tissue covering apical tooth roots, grows by apposition to maintain the tooth in its occlusal position. We hypothesized that resident cementocytes would show morphological changes in response to cementum apposition, possibly implicating a role in cementum biology. Mandibular first molars were induced to super-erupt (EIA) by extraction of maxillary molars, promoting rapid new cementum formation. Tissue and cell responses were analyzed at 6 and/or 21 days post-procedure (dpp). High-resolution micro-computed tomography (micro-CT) and confocal laser scanning microscopy showed increased cellular cementum by 21 dpp. Transmission electron microscopy (TEM) revealed that cementocytes under EIA were 50% larger than control cells, supported by larger pore sizes detected by micro-CT. Cementocytes under EIA displayed ultrastructural changes consistent with increased activity, including increased cytoplasm and nuclear size. We applied EIA to Hyp mutant mice, where cementocytes have perilacunar hypomineralization defects, to test cell and tissue responses in an altered mechanoresponsive milieu. Hyp and WT molars displayed similar super-eruption, with Hyp molars exhibiting 28% increased cellular cementum area vs. 22% in WT mice at 21 dpp. Compared to control, Hyp cementocytes featured well-defined, disperse euchromatin and a thick layer of peripherally condensed heterochromatin in nuclei, indicating cellular activity. Immunohistochemistry for cementum markers revealed intense dentin matrix protein-1 expression and abnormal osteopontin deposition in Hyp mice. Both WT and Hyp cementocytes expressed gap junction protein, connexin 43. This study provides new insights into the EIA model and cementocyte activity in association with new cementum formation. Collectively, we demonstrated morphological and ultrastructural changes in cementocytes after super-eruption.