Immunocytochemical and Neurobiological study on Periodontal Nerve Fibers : A Developmental Approach and Experimental Model

1.用PGP 9.5抗体对大鼠切牙牙周Ruffini末梢的生后发育进行了观察。免疫电子显微镜结果提示，牙萌出和咬合力引起的机械刺激可能是牙周Ruffini末端最终分化和成熟的先决条件。在一个实验模型中，人工咬合力很容易诱导牙周Ruffini末端的形成，但经过补充组织修复后，受损的末端形态恢复到正常形态。此外，细小的神经纤维在组织重塑发生时出现，呈串珠状。在一个实验性牙齿模型中，神经可塑性的关键分子生长相关蛋白-43(GAP-43)在牙周Ruffini终末的轴突终末的表达模式发生了变化。在牙齿移动后的第3-5天，在生理条件下缺乏免疫反应的轴突终末出现暂时性的GAP-43免疫反应。牙周Ruffini末梢表达calbindin D28k和calretinin，二者在机械转导中起重要作用。在挤压下牙槽神经的神经损伤模型中，免疫电子显微镜显示神经肽Y在牙周Ruffini末梢的轴突终末表达，神经肽Y通常与交感神经系统中的去甲肾上腺素共存。使用化学浸渍技术的扫描电子显微镜显示了牙周Ruffini末端的三维结构。此外，他们开发了雪旺细胞突起，作为牙周韧带中这些终末的锚。为了获得上述发现，在整个研究项目中使用了由#08457478赠款购买的超微切片机。

1. Postnatal development of periodontal Ruffini endings was investigated in rat incisors by immunoelectron microscopy using PGP 9.5-antibody. The immunoelectron microscopic findings suggested that mechanical stimuli due to tooth eruption and occlusal forces might be a prerequisite for the final differentiation and maturation of the periodontal Ruffini endings.2. In an experimental model, artificial occlusal forces easily induced the forms of the periodontal Ruffini endings, but the damaged terminal formation recovered to normal morphology after complement of tissue repair. Furthermore, thin nerve fibers, beaded in appearance, occurred in the period when tissue remodeling took place.3. In an experimental tooth model, the expression pattern of growth associated protein-43 (GAP-43), a key molecule in neural plasticity, was altered in the axon terminals of the periodontal Ruffini endings. On day 3-5 after tooth movement, immunoreactivity for GAP-43 was temporally found in the axon terminals which lack immunoreaction in physiological conditions.4. The periodontal Ruffini endings exhibited immunoreactivities for calbindin D28k and calretinin, both of which play important roles in mechanotransduction.5. In the nerve injury model to crush inferior alveolar nerves, immunoelectron microscopy revealed the temporal expression of neuropeptide Y,which is usually co-localized in noradrenalin in the sympathetic nervous system, in the axon terminals of the periodontal Ruffini endings.6. Scanning electron microscopy using a chemical maceration technique revealed a three-dimensional structure of the periodontal Ruffini endings. Furthermore, they developed Schwann cell processes which serve as an anchor of these endings in the periodontal ligament.To obtain these findings mentioned above, the ultramicrotome, which was purchased by grant #08457478, was utilized throughout this research project.