Abstract：
Cluster of differentiation 146 (CD146) is known to localize in stem cells and precursor cells of various tissues. In this study, to analyze the function of CD146 in odontoblast differentiation, immunohistochemical localization of CD146 was examined during rat molar tooth development and after cavity preparation. At the cap and bell stages, many CD146-positive cells were visible around the blood vessels in the dental papillae. On Postnatal day 2, osterix-positive odontoblasts were arranged in the dentin sialoprotein (DSP)-positive predentin, and many CD146-positive cells were observed near these odontoblasts with blood vessels. Some perivascular CD146-positive cells overlapped with Smad4-positive cells. However, the immunoreactivity for alpha-smooth muscle actin (α-SMA), one of the markers for undifferentiated cells, was negligible. Furthermore, the number of these cells decreased in the dental pulp on Postnatal day 28. On Day 4 after cavity preparation, Osterix-positive odontoblasts appeared lining the reparative dentin. Most of the blood vessels near the reparative dentin showed immunoreactivities for CD146. Reparative odontoblasts actively formed DSP-positive dentin matrix because these cells were positive for Smad4 and Osterix, but not for α-SMA. After 7 days, the number of CD146-positive cells near blood vessels decreased in the dental pulp beneath the cavity. These results suggest that the CD146 is expressed in the perivascular area of the dental pulp and induces vascularization in the vicinity of dentin formation, and some CD146-positive cells are activated by the bone morphogenetic protein signaling pathway and differentiate into odontoblasts in the early stages of dentin formation and repair.
摘要：
已知分化簇146(CD146)定位于各种组织的干细胞和前体细胞中。在这项研究中,分析CD146在成牙本质细胞分化中的作用,在大鼠磨牙发育期间和腔准备后检查了CD146的免疫组织化学定位。在帽子和钟声阶段，在牙乳头的血管周围可见许多CD146阳性细胞。在出生后第2天，将osterix阳性的成牙本质细胞排列在牙本质唾液酸蛋白（DSP）阳性的牙本质蛋白中，在这些带有血管的成牙本质细胞附近观察到许多CD146阳性细胞。一些血管周围CD146阳性细胞与Smad4阳性细胞重叠。然而,α-平滑肌肌动蛋白（α-SMA）的免疫反应性，未分化细胞的标记之一，微不足道。此外，出生后第28天，这些细胞在牙髓中的数量减少。在空腔准备后的第4天，Osterix阳性成牙本质细胞出现在修复性牙本质上。修复性牙本质附近的大多数血管对CD146具有免疫反应性。修复成牙本质细胞积极形成DSP阳性牙本质基质，因为这些细胞对Smad4和Osterix呈阳性，但不是α-SMA。7天后,口腔下方牙髓中血管附近的CD146阳性细胞数量减少。这些结果表明，CD146在牙髓的血管周围区域表达，并在牙本质形成附近诱导血管形成，一些CD146阳性细胞在牙本质形成和修复的早期阶段被骨形态发生蛋白信号通路激活并分化为成牙本质细胞。
