Histological Study of Genesis of the Mice Oral Vestibule

研究背景：前庭板（vestibular lamina, VL）及牙板（dental lamina, DL）皆是由口腔中原發性上皮帶（primary epithelial band）發育而來。先前許多研究指出，前庭板與牙板最初是由口腔內初始上皮帶與其下間葉組織間的某種上皮間葉交互作用（epithelial-mesenchymal interaction而來），但其正確的機制仍待研究證實。研究目的：在本研究中我們希望瞭解到視網膜母細胞瘤家族（retinoblastoma family, Rb）及E2促進結合因子（E2 Promoter binding factor, E2F）如何調節此控制前庭板增生與分化而導致口腔前庭形成的訊息。研究方法：使用免疫組織化學顯微鏡及共焦雷射掃瞄式顯微鏡來觀察受精後11天至14天，老鼠胎兒其發育中的前庭板，其中前者的發現並與觀察發育中牙板及牙胚的結果進行比較。另外，對於受精後13天的老鼠胎兒則使用穿透式電子顯微鏡來觀察，藉此以明瞭發育中前庭板內角質細胞（keratocyte）分化的過程。研究結果：此研究中我們得到以下結果：（1）EFG、EGFα、EGFR、PCNA、FGF2、pRb及EFFR1-4可在發育中組織內發現。（2）EGF家族與FGF2在誘導前庭板的發生及細胞分化上佔有不可或缺的角色。（3）FGFR1廣泛地存在原發性上皮帶上，但卻強型表現在受精後12-14天老鼠胎兒中的前庭板及牙板（釉質器官）中。相對起來，EGFR則可在受精後13天老鼠胎兒分化中的前庭板內發現。（4）pRb的表現主要位於受精13天之老鼠胎兒其前庭板的基底上層（suprabasal layer），此與CK-10的表現及前庭板生發層（stratum germinativum）細胞內之含有角質透明（keratohyaline）的構造一致。結論：在此研究中，吾人認為存在一機制於FGFR1來調節pRb以誘導前庭板及牙板（釉質器官）的細胞增生，並促使角質細胞的分化甚至前庭板內已角化細胞的脫落。

關鍵字

口腔前庭；發生起源；老鼠；組織學

並列摘要

Background: Both the vestibular lamina (VL) and dental lamina (DL) develop from the primary epithelial band of the oral cavity. Previous studies have reported that VL and DL were initiated by certain epithelial-mesenchymal interactions between the primary epithelial band of the oral cavity and underlying mesenchyme; however, the exact mechanisms remain to be elucidated. Aims: Here we studied how the retinoblastoma (Rb) family and E2 promoter binding factor (E2F) regulate signals that control and regulate the proliferation and differentiation of the VL leading to the formation of the oral vestibule. Methods: Immunohistochemical light microscopy by the enhanced polymer one-step staining(EPOS) method and confocal laser scanning microscopy by the LsAB labelled streptavidin biotin (LSAB) method were performed on the developing vestibular lamina(VL) of fetal mice at stages from 11 days after fertilization E11 to E14.The immunohistochemical findings were compared with the findings in the developing dental lamina (DL) and tooth germ. Conventional transmission electron microscopy was performed on the E13 fetuses, in an effort to elucidate the differentiation of keratocytes in the developing VL. Results: We found that: 1) EGF, TGF , EGFR, PCNA, FGF2, pRb, and FGFR1-4 were immunolocalized in the developing tissues. 2) Cytokine expression patterns indicated that the EGF family and FGF2 essentially induced VL generation and cell proliferation. 3) FGFR1 as diffusely localized in the primary epithelial band, but was strongly expressed in the E12-14 VL and DL/enamel organ. By contrast, EGFR internalization was observed in the differentiating E13 VL. 4) Expression of pRb was intensely localized in the suprabasal layer of the E13 VL corresponding to CK-10 expression and keratohyaline-containing structures in the VL stratum germinativum cells. Conclusions: We suggest a mechanism in which FGFR1 regulates pRb to induce proliferation of cells in the VL and DL/enamel organ, and, in particular, to incite keratocyte differentiation and subsequent exfoliation of keratinizing VL cells.

並列關鍵字

Oral vestibule ； Genesis ； Mouse ； Histology

國際替代計量

Histological Study of Genesis of the Mice Oral Vestibule

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