Hatakeyama Rie, Oue Hiroshi, Yokoi Miyuki, Ishida Eri, Tsuga Kazuhiro
Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
Department of Dentistry & Oral-Maxillofacial Surgery, Fujita Health University, Toyoake, Aichi, Japan.
Odontology. 2025 Apr;113(2):706-713. doi: 10.1007/s10266-024-01008-x. Epub 2024 Oct 4.
Osteoporosis is a prevalent disease that is associated with increased hip fractures which cause significant decline in quality of life. Tooth loss affects systemic condition such as cognitive function through various mechanism, but the link between tooth loss and femoral bone mineral density is still uncertain. This study aims to investigate whether tooth loss in young mice affects memory function and femoral bone mineral density. Eight-week-old male C57BL/6 J mice were allocated randomly into the control group with sham operation and the tooth-loss group extracted all maxillary molar. Step-through passive avoidance test as cognitive function test, micro-CT analysis and western blotting analysis were performed after 1- and 2-month observation period. Step-through passive avoidance test revealed that the tooth-loss group in 2-month observation period impaired cognitive function. Additionally, micro-CT analysis revealed a significant decrease in both the length of the mandible and bone mineral density in the femur of the tooth-loss group compared to the control group. Claudin-5 level in the hippocampus, which is one of the tight junction markers in blood-brain-barrier, was significantly decreased in the tooth-loss group. The findings of our present study suggested that tooth loss impair cognitive function accompanied by reduced tight-junction marker, mandibular growth and bone mineral density of femur.
骨质疏松症是一种常见疾病，与髋部骨折增加有关，而髋部骨折会导致生活质量显著下降。牙齿脱落通过多种机制影响全身状况，如认知功能，但牙齿脱落与股骨骨密度之间的联系仍不明确。本研究旨在调查年轻小鼠的牙齿脱落是否会影响记忆功能和股骨骨密度。将8周龄雄性C57BL/6 J小鼠随机分为假手术对照组和拔除所有上颌磨牙的牙齿脱落组。在1个月和2个月的观察期后，进行作为认知功能测试的穿梭式被动回避试验、显微CT分析和蛋白质印迹分析。穿梭式被动回避试验显示，在2个月观察期内，牙齿脱落组的认知功能受损。此外，显微CT分析显示，与对照组相比，牙齿脱落组的下颌骨长度和股骨骨密度均显著降低。血脑屏障紧密连接标志物之一的海马中Claudin-5水平在牙齿脱落组中显著降低。我们目前的研究结果表明，牙齿脱落会损害认知功能，同时伴有紧密连接标志物减少、下颌骨生长和股骨骨密度降低。
