Immunohistochemical localization of α-smooth muscle actin during rat molar tooth development
Immunohistochemical localization of α-smooth muscle actin during rat molar tooth development
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DOI：
10.1369/jhc.6a6980.2006
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发表时间：
2006-12-01
影响因子：
3.2
通讯作者：
Ozawa, Hidehiro
中科院分区：
文献类型：
--
作者：
Hosoya, Akihiro;Nakamura, Hiroaki;Ozawa, Hidehiro
牙囊含有间充质细胞，可分化为成骨细胞、成牙骨质细胞和成纤维细胞。然而，这些间充质细胞的特性仍不清楚。已知α-平滑肌肌动蛋白(α-SMA)定位于干细胞和各种组织的前体细胞。本研究对大鼠磨牙发育过程中a-SMA的免疫组织化学定位进行了研究，以确定牙囊中未分化细胞的特征。分别于胚胎(E)15-20天和出生后(P)7-28天采集大鼠下颌骨。石蜡包埋切片进行α-SMA、Periostin、Run相关转录因子-2(Runx2)、组织非特异性碱性磷酸酶(TNAP)和骨涎蛋白(BSP)免疫组织化学染色。蕾状期和帽状期几乎未检测到A-SMA定位。钟状早期，颈环周围的牙囊内可见α-SMA阳性细胞。在钟状晚期至牙根形成早期(P14)，这些细胞在整个牙囊中均可检测到，但在P28时仅限于根尖区域。α-SMA和Periostin双重免疫染色显示，α-SMA阳性细胞定位于Periostin阳性区域的外侧。在a-SMA阳性区域可见Runx2阳性细胞。在牙囊中，TNAP阳性细胞比Runx2阳性细胞更靠近牙槽骨。BSP在成骨细胞和牙槽骨基质中均有表达。这些结果表明，a-SMA阳性细胞定位于牙囊的牙槽骨侧，可能在牙槽骨的形成中起作用。
The dental follicle contains mesenchymal cells that differentiate into osteoblasts, cementoblasts, and fibroblasts. However, the characteristics of these mesenchymal cells are still unknown. alpha-Smooth muscle actin (alpha-SMA) is known to localize in stem cells, and precursor cells of various tissues. In the present study, to characterize the undifferentiated cells in the dental follicle, immunohistochemical localization of a-SMA was examined during rat molar tooth development. Rat mandibles were collected at embryonic days (E) 15-20 and postnatal days (P) 7-28. Immunohistochemical stainings for alpha-SMA, periostin, Runt-related transcription factor-2 (Runx2), tissue nonspecific alkaline phosphatase (TNAP), and bone sialoprotein (BSP) were carried out using paraffin-embedded sections. a-SMA localization was hardly detected in the bud and cap stages. At the early bell stage, alpha-SMA-positive cells were visible in the dental follicle around the cervical loop. At the late bell to early root formation stage (P14), these cells were detected throughout the dental follicle, but they were confined to the apical root area at P28. Double immunostaining for alpha-SMA and periostin demonstrated that alpha-SMA-positive cells localized to the outer side of periostin-positive area. Runx2-positive cells were visible in the a-SMA-positive region. TNAP-positive cells in the dental follicle localized nearer to alveolar bone than Runx2-positive cells. BSP was detected in osteoblasts as well as in alveolar bone matrix. These results demonstrate that a-SMA-positive cells localize on the alveolar bone side of the dental follicle and may play a role in alveolar bone formation.