Micro-CT evaluation of tooth, calvaria and mechanical stress-induced tooth movement in adult Runx2/Cbfa1 heterozygous knock-out mice.
Micro-CT evaluation of tooth, calvaria and mechanical stress-induced tooth movement in adult Runx2/Cbfa1 heterozygous knock-out mice.
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DOI：
10.11480/jmds.510114
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发表时间：
2004-03
影响因子：
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通讯作者：
C. J. Chung;K. Tsuji;A. Nifuji;T. Komori;K. Soma;M. Noda
中科院分区：
文献类型：
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作者：
C. J. Chung;K. Tsuji;A. Nifuji;T. Komori;K. Soma;M. Noda
Runx 2/Cbfa 1是成骨细胞分化和骨形成所必需的。Runx 2缺失小鼠（Runx 2（-/-））完全缺乏矿化组织，出生后不久死亡，而Runx 2杂合敲除小鼠（Runx 2（+/-））存活，但显示骨骼系统的形态学缺陷，如在人类锁骨颅骨发育不良（CCD）中观察到的。本研究的目的是阐明Runx 2在成人矿化组织中的作用，并揭示Runx 2杂合缺失对牙齿移动的反应的独特特征。因此，我们使用软X线和显微CT检查成人Runx 2（+/-）的颅骨、牙齿和牙周组织。此外，对机械负荷引起的牙齿移动进行了评价。成人Runx 2（+/-）中，上颌第一磨牙的冠根比明显低于野生型（WT）。同时观察到根系形态的不规则性。与WT相比，颅骨狭窄，顶骨较薄。在移动距离方面，Runx 2（+/-）和WT之间的机械应力诱导的牙齿移动相似。然而，虽然WT中第一周和第三周之间的旋转运动增加，但在Runx 2（+/-）小鼠中没有改变。这些数据表明Runx 2在成年期的颅骨和牙齿发育中起作用。
Runx2/Cbfa1 is essential for osteoblast differentiation and bone formation. Runx2 null mice (Runx2(-/-)) completely lack mineralized tissue and die soon after birth, whereas Runx2 heterozygous knock-out mice (Runx2(+/-)) stay alive but show morphological defects in the skeletal system as observed in cleidocranial dysplasia (CCD) in humans. The aim of this study is to elucidate the role of Runx2 in adult mineralized tissue and also to reveal the distinct features of heterozygous deletion of Runx2 in response to tooth movement. Therefore, we examined the cranium, tooth and the periodontium in adult Runx2(+/-) using soft X-ray and micro-CT. In addition, tooth movement induced by mechanical loading was evaluated. In adult Runx2(+/-), crown:root ratio of the first maxillary molar was significantly lower than that of wild type (WT). Irregularities in root morphology was also observed. The cranium was narrow with thin parietal bone compared to WT. Mechanical stress-induced tooth movement was similar between Runx2(+/-) and WT in terms of movement distance. However, while rotational movement between the first and third week was increased in WT, it was not altered in Runx2(+/-) mice. These data indicate that Runx2 plays a role in cranium and the tooth development in adulthood.