The function of parvalbumin and calcitonin gene-related peptide in the inflamed pulp

正常大鼠牙髓内含有小白蛋白免疫反应(IR)神经纤维。在根髓中，IR神经纤维粗大光滑。这些神经纤维投射到冠髓，并在亚牙髓母细胞层中形成亚神经母细胞神经丛。他们将静脉曲张的终末送到成牙本质细胞层。免疫电子显微镜显示小白蛋白阳性神经根轴突粗大，有髓鞘。在成牙本质细胞层，IR突起与成牙本质细胞的胞体和突起紧密接触。牙髓暴露后1~3d，牙髓内无小白蛋白阳性神经纤维。5-7天时，牙髓小白蛋白阳性神经纤维增多，在炎症组织下形成神经丛。这些神经纤维大多呈细长曲张状。牙髓暴露后14天，牙髓内可见大量炎性细胞。小白蛋白免疫反应阳性神经纤维数量在这一时期减少。他们在根髓中观察到，但在冠髓中没有观察到。30~60d时，根尖形成脓肿。IR神经纤维在脓肿周围形成神经丛。免疫荧光双标记法显示，小白蛋白和降钙素基因相关肽(CGRP)免疫反应阳性神经纤维在各发育阶段的分布模式相似。提示小白蛋白和降钙素基因相关肽在牙髓炎症中起重要作用。

The tooth pulp in the normal rat contained parvalbumin-immunoreactive (ir) nerve fibers. In the root pulp, ir nerve fibers had a thick and smooth appearance. These nerve fibers projected to the coronal pulp, and made subodontoblastic nerve plexuses in the subodontoblastic layer. They sent their varicose terminals to the odontoblastic layer. An immunoelectron microscopic study revealed that parvalbumin-ir radicular axons were thick and myelinated. In the odontoblastic layer, ir neurites made close contact with cell bodies and processes of odontoblasts. At 1-3 days after the pulp exposure, the tooth pulp was devoid of parvalbumin ir nerve fibers. At 5-7 days, however, parvalbumin-ir pulpal nerve fibers increased in number and made nerve plexuses beneath the inflamed tissue. These nerve fibers mostly had a thin and varicose appearance. At 14 days after the pulp exposure, inflammatory cells were observed throughout the tooth pulp. Parvalbumin-ir nerve fibers decreased in number at this stage. They observed in the root pulp but not the coronal pulp. At 30-60 days, the abscess was formed at the root apex. Ir nerve fibers made plexuses around the abscess. A double immunofluorescence method demonstrated that the distribution patterns of parvalbumin- and calcitonin gene-related peptide (CGRP)-ir nerve fibers were similar at all stage. The present study suggests that parvalbumin and CGRP have an important role for the inflammation in the tooth pulp.