Partanen A M, Thesleff I
Institute of Dentistry, University of Helsinki, Finland.
Int J Dev Biol. 1989 Mar;33(1):165-72.
The effects of various growth factors on tooth development were studied in organ cultures of mouse embryonic tooth germs. Transferrin was shown to be a necessary growth factor for early tooth morphogenesis. Transferrin was required for the development of bud- and early cap-staged teeth, and it was shown to be the only serum protein that was needed by early cap-staged teeth in organ culture. Promotion of tooth morphogenesis and dental cell differentiation was shown to be based on the stimulation of cell proliferation. The roles of polypeptide growth factors in tooth development were studied by adding these factors to the transferrin-containing chemically-defined culture medium which supports early tooth morphogenesis and cell differentiation. Fibroblast growth factor or platelet-derived growth factor did not affect cell proliferation or morphogenesis of tooth germs in culture. On the contrary, epidermal growth factor (EGF) stimulated cell proliferation in tooth explants, but at the same time inhibited tooth morphogenesis and dental cell differentiation. Autoradiographic localization of proliferating cells revealed that dental tissues responded to EGF with different proliferation rates. The responsiveness to EGF was stage-dependent, early cap-staged teeth were sensitive to EGF but late cap-staged and bell-staged teeth developed normally in the presence of EGF in the culture medium. The presence and distribution of receptors for both transferrin and EGF were studied in mouse embryonic teeth at various developmental stages by incubating freshly-separated tooth germs with 125Iodine-labeled transferrin or EGF, and then processing the tissues for autoradiography.(ABSTRACT TRUNCATED AT 250 WORDS)
在小鼠胚胎牙胚的器官培养中研究了各种生长因子对牙齿发育的影响。转铁蛋白被证明是早期牙齿形态发生所必需的生长因子。转铁蛋白是芽期和早期帽状期牙齿发育所必需的，并且它是器官培养中早期帽状期牙齿唯一所需的血清蛋白。牙齿形态发生和牙细胞分化的促进作用被证明是基于对细胞增殖的刺激。通过将这些因子添加到支持早期牙齿形态发生和细胞分化的含转铁蛋白的化学成分确定的培养基中，研究了多肽生长因子在牙齿发育中的作用。成纤维细胞生长因子或血小板衍生生长因子对培养中的牙胚细胞增殖或形态发生没有影响。相反，表皮生长因子（EGF）刺激牙外植体中的细胞增殖，但同时抑制牙齿形态发生和牙细胞分化。增殖细胞的放射自显影定位显示，牙齿组织对EGF的反应具有不同的增殖率。对EGF的反应性是阶段依赖性的，早期帽状期牙齿对EGF敏感，但在培养基中存在EGF的情况下，晚期帽状期和钟状期牙齿正常发育。通过用125碘标记的转铁蛋白或EGF孵育新鲜分离的牙胚，然后对组织进行放射自显影，研究了不同发育阶段小鼠胚胎牙齿中转铁蛋白和EGF受体的存在和分布。（摘要截短于250字）
