General investigation of malocclusion in the aspect of age-related expression mechanism

细胞外基质通过拔除对牙诱导大鼠单侧下颌磨牙咬合功能减退，通过免疫组化分析，阐明咬合功能减退对牙周韧带蛋白多糖含量变化的影响。由于咬合功能的丧失，牙周韧带中的蛋白多糖减少，这些结果表明蛋白多糖与咬合功能密切相关，在组织稳态或组织重塑中发挥重要作用。微血管我们用大鼠磨牙咬合功能减退模型研究了咬合刺激对牙周韧带微血管的影响。牙合功能减退导致牙周膜变窄，血管缩小，血管数量减少。本研究揭示了功能障碍导致血管收缩因子内皮素和血管舒张因子一氧化氮合酶（NOS）表达升高的机制，并提出了其与血管舒张因子一氧化氮合酶（NOS）表达的关系。牙周机械感受器采用离体颌神经制剂研究了牙周机械感受器的神经生理特性。本研究结果证实了实验性咬合功能障碍对牙周机械信号的影响。为了阐明机械应力下骨重塑的机制，我们将培养的成骨细胞置于剪切应力下，发现细胞内Ca^<2+>的增强取决于拉伸激活通道的特性，并由肌动蛋白丝等细胞骨架调节。我们还阐明了大鼠牙根功能减退、牙槽骨重塑和牙齿的生理运动。并且，在功能障碍状态下的牙齿运动实验表明，轻微的正畸力有助于保护健全的牙周组织。少

Extracellular matrixOcclusal hypofunction of rat unilateral mandibular molars was induced by extraction of the opposing teeth, and immunohistochemical analyzes were performed to clarify the influence of occlusal hypofunction on the changes of proteoglycan content in the periodontal ligament.proteoglycan decreased in the periodontal ligament due to loss of occlusal function, and these results suggest that proteoglycans are closely related to occlusal function and play important roles in tissue homeostasis or tissue remodeling.MicrovasculatureWe examined the effect of occlusal stimuli on the microvasculature of the periodontal ligament using a model of occlusal hypofunction in rat molars. The occlusal hypofunction caused narrowing of the periodontal membrane and reduction in the vessel size with decrease in the number of blood vessles. In this study, a mechanism is revealed that hypofunction would result in increase of the expression of endothelin, a potent vasoconstrictive factor, furth … More ermore it also suggested the relation to expression of nitric oxide synthase(NOS), a vasodilator factor.Periodontal mechanoreceptorsThe neurophysiological properties of the periodontal mechanoreceptors were studied using an in vitro jaw-nerve preparation. Results of this study have demonstrated the effects of experimental occlusal hypofunction on the periodontal mechanical signaling. Moreover, changes related to growth and development have also been investigatedActivity of bone formationIn order to clarify the mechanism of bone remodeling under mechanical stress, cultured osteoblastic-cells were subjected to shear stress, in which we have revealed that the enhancement of intracellular Ca^<2+> depended on the property of stretch-activated channel and were modulated by the cytoskeleton such as actin filament.We also elucidated the hypofunctional condition of the root, remodeling of the alveolar bone and the physiological tooth movement in rats. And, the experimental tooth movements under hypofunctional condition have made it more obvious that light orthodontic forces contribute to the conservation of sound periodontal tissue. Less