Inoue M, LeGeros R Z, Hoffman C, Diamond K, Rosenberg P A, Craig R G
Department of Biomaterials, and Biomimetics, New York University College of Dentistry, 345 East 24th Street, New York, New York 10010, USA.
J Biomed Mater Res A. 2004 Apr 1;69(1):172-9. doi: 10.1002/jbm.a.20139.
Cells within the periodontal ligament have the potential to regenerate a periodontal connective tissue attachment on pathologically exposed root surfaces as well as on several material surfaces including titanium. However, rather than a periodontal connective tissue attachment, a fibrous encapsulation or chronic inflammatory response has been reported at the material connective tissue interface for most dental materials. Cementum is the first tissue of the periodontal connective tissue attachment to develop and the secretion of enamel matrix related proteins on the newly mineralized dentin surface precedes and is thought to induce cementum formation. Enamel matrix-related proteins may also function in the adult because the application of an acid extract of porcine enamel protein matrix (Emdogain(R), EMD) on pathologically exposed root surfaces has been shown to result in cementum regeneration. Therefore, the objective of the present study was to determine whether the application of EMD to materials that do not normally support cementogenesis in vivo would alter the in vitro phenotype of periodontal ligament (PDL) cells including the synthesis of cementum-associated extracellular matrix proteins. Primary PDL cells were established from 21-day-old Sprague-Dawley rats, and were cultured on four materials commonly encountered in dental practice (gutta percha, calcium hydroxide, amalgam, and super EBA cement) with and without the application of EMD. After 7 or 14 days of culture, total-DNA content, collagen synthesis, alkaline phosphatase activity, and the synthesis of a 42-kDa cementum-associated extracellular matrix protein were determined. PDL cells cultured on all materials had decreased total DNA content. The application of EMD further decreased total DNA content. PDL cells cultured on gutta percha and calcium hydroxide with the application of EMD had similar levels of collagen synthesis and alkaline phosphatase activity but also expressed a 42-kDa cementum extracellular matrix-associated protein when compared to the other groups. These results suggest that EMD can alter the phenotype of PDL cells when cultured on these dental materials.
牙周膜内的细胞有潜力在病理暴露的根面以及包括钛在内的多种材料表面上再生牙周结缔组织附着。然而，对于大多数牙科材料而言，在材料与结缔组织界面处报道的是纤维性包囊或慢性炎症反应，而非牙周结缔组织附着。牙骨质是牙周结缔组织附着中最先发育的组织，釉基质相关蛋白在新矿化的牙本质表面的分泌先于牙骨质形成，并且被认为可诱导牙骨质形成。釉基质相关蛋白在成年期可能也有作用，因为已表明在病理暴露的根面上应用猪釉质蛋白基质酸提取物（Emdogain®，EMD）可导致牙骨质再生。因此，本研究的目的是确定将EMD应用于体内通常不支持牙骨质生成的材料是否会改变牙周膜（PDL）细胞的体外表型，包括与牙骨质相关的细胞外基质蛋白的合成。从21日龄的Sprague-Dawley大鼠建立原代PDL细胞，并在牙科实践中常见的四种材料（牙胶、氢氧化钙、汞合金和超级EBA水门汀）上培养，添加或不添加EMD。培养7天或14天后，测定总DNA含量、胶原蛋白合成、碱性磷酸酶活性以及一种42 kDa与牙骨质相关的细胞外基质蛋白的合成。在所有材料上培养的PDL细胞总DNA含量均降低。应用EMD进一步降低了总DNA含量。与其他组相比，在添加EMD的牙胶和氢氧化钙上培养的PDL细胞具有相似水平的胶原蛋白合成和碱性磷酸酶活性，并且还表达一种42 kDa与牙骨质细胞外基质相关的蛋白。这些结果表明，当在这些牙科材料上培养时，EMD可改变PDL细胞的表型。
