Ichikawa-Kato Tomoka, Hara Tetsuya, Yamada-Kubota Chie, Kuwahara Miho, Murakami Asuka, Minagi Shogo
Department of Occlusal and Oral Functional Rehabilitation, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
J Prosthodont Res. 2025 Apr 14;69(2):243-248. doi: 10.2186/jpr.JPR_D_23_00231. Epub 2024 Aug 27.
The lack of occlusal support reportedly reduces cognitive function; however, the underlying mechanisms remain unclear. The locus coeruleus, which is located adjacent to the trigeminal mesencephalic nucleus, secretes noradrenaline throughout the brain. In this study, we evaluated the effects of noradrenaline in the hippocampus and cerebral cortex on cognitive decline following tooth extraction in rats.
We performed passive avoidance experiments on male Wistar rats with extracted maxillary molars and determined the neuron density in the locus coeruleus and trigeminal mesencephalic nucleus using immunostaining and Nissl staining, respectively. We also assessed noradrenaline concentrations in the hippocampus and cerebral cortex using enzyme-linked immunosorbent assay.
In the passive avoidance experiment, the latency in the bright compartment was significantly shorter (P < 0.05) in the extraction group than in the control group. The numbers of cells in the locus coeruleus and trigeminal nucleus were significantly lower (P < 0.05) in the extraction group compared to those in the control group. The noradrenaline levels in the hippocampus and cerebral cortex were also significantly lower (P < 0.05) in the extraction group than those in the control group.
The lack of occlusal support associated with tooth extraction reduces the number of cells in the trigeminal mesencephalic nucleus and locus coeruleus, which may reduce the supply of noradrenaline to the cerebral cortex and hippocampus, leading to a decline in cognitive function.
据报道，缺乏咬合支持会降低认知功能；然而，其潜在机制仍不清楚。蓝斑位于三叉神经中脑核附近，可向全脑分泌去甲肾上腺素。在本研究中，我们评估了大鼠拔牙后海马体和大脑皮质中去甲肾上腺素对认知功能衰退的影响。
我们对拔除上颌磨牙的雄性Wistar大鼠进行了被动回避实验，并分别使用免疫染色和尼氏染色法测定了蓝斑和三叉神经中脑核中的神经元密度。我们还使用酶联免疫吸附测定法评估了海马体和大脑皮质中的去甲肾上腺素浓度。
在被动回避实验中，拔牙组在明室中的潜伏期明显短于对照组（P < 0.05）。与对照组相比，拔牙组蓝斑和三叉神经核中的细胞数量明显减少（P < 0.05）。拔牙组海马体和大脑皮质中的去甲肾上腺素水平也明显低于对照组（P < 0.05）。
与拔牙相关的咬合支持缺乏会减少三叉神经中脑核和蓝斑中的细胞数量，这可能会减少大脑皮质和海马体中去甲肾上腺素的供应，导致认知功能下降。
