【摘要】：背景：牙齒發(fā)育包括一系列至關(guān)重要的有序的相互作用，發(fā)生在口腔上皮與顱神經(jīng)嵴間充質(zhì)細(xì)胞之間。研究已經(jīng)證實(shí)原發(fā)性上皮帶在牙齒發(fā)育中的誘導(dǎo)作用，并且這些相互作用，包括生長(zhǎng)因子、同源基因和轉(zhuǎn)錄因子的高度協(xié)調(diào)表達(dá)，逐步誘導(dǎo)牙原基在牙弓內(nèi)形成一個(gè)具有特定大小、形狀和位置的復(fù)雜礦化結(jié)構(gòu)。有研究在小鼠體內(nèi)標(biāo)記一種基因來(lái)追蹤神經(jīng)嵴細(xì)胞的遷移與分化，結(jié)果證明在蕾狀期，顱神經(jīng)嵴源外胚間充質(zhì)對(duì)于牙乳頭和其周圍的牙囊的形成有重要作用。研究證明，成牙本質(zhì)細(xì)胞，牙本質(zhì)基質(zhì)以及大部分的牙髓組織都來(lái)源于顱神經(jīng)嵴。 牙齒損傷的機(jī)制包括誘導(dǎo)細(xì)胞凋亡，活化的免疫反應(yīng)和牙齒組織生理的變化，在多數(shù)情況下，凋亡細(xì)胞迅速清除。并未誘發(fā)炎癥反應(yīng)。而牙齒組織重建的機(jī)制類似于牙齒發(fā)育的過(guò)程。髓腔的結(jié)構(gòu)重建發(fā)生于牙齒修復(fù)性牙本質(zhì)沉積。成牙本質(zhì)層的細(xì)胞凋亡明顯多于牙髓的其它部位。由于細(xì)胞凋亡而消失的成牙本質(zhì)細(xì)胞層有可能產(chǎn)生死亡信號(hào)，導(dǎo)致同時(shí)臨近的祖細(xì)胞消失。損傷發(fā)生后，，干細(xì)胞從鄰近的儲(chǔ)存處轉(zhuǎn)移至創(chuàng)傷修復(fù)區(qū)，此處出現(xiàn)大量的干細(xì)胞。成牙本質(zhì)細(xì)胞和鄰近的祖細(xì)胞由于細(xì)胞凋亡而消失，這引起牙髓干細(xì)胞遷移至損傷區(qū)域，在此處它們分化成成牙本質(zhì)樣細(xì)胞，從而保證牙髓的重建。 目的：研究釉質(zhì)基質(zhì)蛋白（Enamel Matrix Proteins，EMPs）對(duì)人脫落乳牙牙髓干細(xì)胞（stem cells from human exfoliated dediduous teeth，SHED）體外增殖分化能力的影響。方法：利用酶消化法聯(lián)合組織塊法獲得脫落乳牙牙髓干細(xì)胞，并進(jìn)行形態(tài)學(xué)觀察。三氯乙酸法制備EMPs，用不同濃度的EMPs對(duì)SHED進(jìn)行誘導(dǎo)，利用四唑鹽比色法（MTT）檢測(cè)并分析誘導(dǎo)后的SHED增殖活性的變化，檢測(cè)經(jīng)誘導(dǎo)后的培養(yǎng)液中堿性磷酸酶（ALP）。RT-PCR檢測(cè)牙本質(zhì)涎磷蛋白（dentin sialophosphoprotein,DSPP）及牙本質(zhì)基質(zhì)蛋白1(dentin matrix protein1, DMP-1）的mRNA表達(dá)。結(jié)果：人脫落乳牙牙髓干細(xì)胞呈集落生長(zhǎng)，并且在體外具有一定的自我增殖能力。EMPs對(duì)乳牙牙髓干細(xì)胞的增殖無(wú)明顯影響，而能夠顯著提高ALP的活性，并呈現(xiàn)一定的劑量依賴性。經(jīng)EMPs誘導(dǎo)后，細(xì)胞相對(duì)高表達(dá)DSPP、DMP-1mRNA。結(jié)論：EMPs對(duì)于SHED向成牙本質(zhì)樣分化具有積極作用。
[Abstract]:Background: tooth development includes a series of important ordered interactions between oral epithelium and cranial neural crest mesenchymal cells. Studies have demonstrated the induction of primary upper belt in tooth development, and these interactions, including the highly coordinated expression of growth factors, homologous genes and transcription factors, A complex mineralized structure with a specific size, shape and position was gradually induced to form in the dental arch. A gene was labeled in mice to track the migration and differentiation of neural crest cells. The results showed that the extracellular mesenchymal of cranial neural crest was important for the formation of dental papilla and its surrounding dental sac in the bud stage. It has been shown that odontoblast, dentin matrix and most of dental pulp come from cranial nerve crest. The mechanisms of tooth injury include inducing apoptosis, activated immune response and physiological changes of tooth tissue. In most cases, apoptotic cells are eliminated rapidly. No inflammatory response was induced. The mechanism of tooth tissue reconstruction is similar to the process of tooth development. The structural reconstruction of the pulp cavity occurs when the dentin is restored. The apoptosis of dentin layer was much more than that of other parts of dental pulp. The layer of odontoblast which disappeared due to apoptosis may produce death signal, resulting in the disappearance of adjacent progenitor cells at the same time. After the injury, stem cells are transferred from nearby stores to the wound repair area, where a large number of stem cells are present. The odontoblast and adjacent progenitor cells disappear due to apoptosis, which causes dental pulp stem cells to migrate to the damaged region, where they differentiate into dentin-like cells, thus ensuring dental pulp reconstruction. Aim: to study the effect of enamel matrix protein (Enamel Matrix Proteins,EMPs) on the proliferation and differentiation of human deciduous dental pulp stem cells (stem cells from human exfoliated dediduous teeth,SHED) in vitro. Methods: pulp stem cells of deciduous teeth were obtained by enzyme digestion combined with tissue block method. EMPs, was prepared by trichloroacetic acid and SHED was induced with different concentrations of EMPs. The proliferation activity of SHED was detected and analyzed by (MTT) with tetrazolium salt colorimetry. The expression of mRNA in dentin sialophosphorus protein (dentin sialophosphoprotein,DSPP) and dentin matrix protein 1 (dentin matrix protein1, DMP-1) was detected by alkaline phosphatase (ALP). RT-PCR). Results: human deciduous dental pulp stem cells grew in colony and had the ability of self-proliferation in vitro. EMPs had no obvious effect on the proliferation of deciduous dental pulp stem cells, but could significantly increase the activity of ALP. And showed a certain dose dependence. After induction by EMPs, the expression of DSPP,DMP-1mRNA. in the cells was relatively high. Conclusion: EMPs plays a positive role in the odontoid differentiation of SHED.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：R780.2

【參考文獻(xiàn)】

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1 鄒慧儒;張?zhí)m成;秦宗長(zhǎng);楊學(xué)斌;Steven Brookes;;釉基質(zhì)蛋白組成及誘導(dǎo)細(xì)胞分化研究進(jìn)展[J];中國(guó)組織工程研究;2012年16期

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