Purpose: Circadian rhythm is associated with the pathogenesis of systemic disease and bone mineral metabolism. This study aimed to radiographically evaluate morphological characteristics of the interalveolar septum in circadian rhythm deficient animals.

Methods: Heads of 10 brain and muscle arnt-like protein-1 (BMAL1)-knockout (KO) mice and 10 wild-type mice sacrificed at 36 weeks were imaged using micro-computed tomography. The mean depth from the cementoenamel junction to the alveolar ridge (virtual bone sounding: VBS) of the interalveolar septum between the first and second molars, and the bone mineral density (BMD) of the interalveolar septum and the mandibular inferior cortex region were calculated. Tooth diameter was also measured.

Results: The VBS of the interalveolar septum in the BMAL1-KO mice was significantly deeper than that in wild-type mice. The BMD in the BMAL1-KO mice was significantly lower than in the wild-type mice in both regions. No significant difference was observed in tooth diameter between BMAL1-KO and wild-type mice.

Conclusion: These results suggest that low BMD in the interalveolar septum accelerates bone resorption in the interalveolar septum in BMAL1-KO mice.

目的：昼夜节律与全身性疾病和骨矿物质代谢的发病机制有关。这项研究旨在射线照相评估昼夜节律缺乏动物的肺泡间隔的形态学特征。

方法：用微计算机断层摄影术对在36周处死的10只脑和肌肉arnt样蛋白1（BMAL1）敲除（KO）小鼠和10只野生型小鼠的头部进行成像。计算从第一磨牙和第二磨牙之间的牙槽间隔的牙釉质接合处到牙槽的平均深度（虚拟骨探测：VBS），以及牙槽间隔和下颌下皮质区域的骨矿物质密度（BMD）。还测量了牙齿直径。

结果： BMAL1-KO小鼠的肺泡间隔的VBS明显比野生型小鼠的深。在两个区域中，BMAL1-KO小鼠的BMD均显着低于野生型小鼠。在BMAL1-KO和野生型小鼠之间，没有观察到牙齿直径的显着差异。

结论：这些结果表明，BMAL1-KO小鼠的肺泡隔中低BMD促进了肺泡隔中的骨吸收。