Wöltgens J H, Lyaruu D M, Bervoets T J, Bronckers A L
Department of Oral Cell Biology, Academic Center for Dentistry (ACTA), Vrije Universiteit, Amsterdam, The Netherlands.
Scanning Microsc. 1993 Sep;7(3):1009-16.
Hamster first hamster molar tooth germs in early secretory stage of amelogenesis were cultured for one day in vitro at 6 degrees C, 22 degrees C, 37 degrees C or 45 degrees C in the presence of 3H-proline, 45Ca and 32P-orthophosphate. Other explants were cultured without these labels and after culture examined by histology. The highest temperature tested was lethal to the explants, decreased total dry weight and rapidly increased total uptake of the radiolabelled mineral ions, probably merely due to physicochemical modification of the existing preculture minerals. Optimal synthesis and secretion of amelogenins were measured at physiological temperature (37 degrees C). Effects of exposure to both temperatures below the physiological value were virtually reversible when explants were grown at physiological temperature (37 degrees C) for another day. However, amelogenin secretion during this recovery period did not reach values as high as those found for the first day in explants initially grown at physiological temperature during the first day. We concluded from the four temperatures examined that the optimal temperature for enamel matrix deposition in vitro was 37 degrees C. At this temperature enamel biosynthesis and its secretion are high. Lowering the temperature slows down the metabolism without any apparent harmful effect. Normal development of the tooth explants in vitro resumes when the culture temperature is restored to physiological levels (37 degrees C). For temporary storage of tooth germ explants prior to any reimplantation, we therefore recommend a temperature of 6 degrees C.
将处于釉质形成早期分泌阶段的仓鼠第一磨牙牙胚在6℃、22℃、37℃或45℃下，于含有3H - 脯氨酸、45Ca和32P - 正磷酸盐的条件下进行一天的体外培养。其他外植体在无这些标记物的情况下培养，培养后进行组织学检查。所测试的最高温度对牙胚外植体具有致死性，降低了总干重，并迅速增加了放射性标记矿物质离子的总摄取量，这可能仅仅是由于预培养时已存在的矿物质发生了物理化学修饰。在生理温度（37℃）下测定了釉原蛋白的最佳合成和分泌。当外植体在生理温度（37℃）下再培养一天时，暴露于低于生理值的两种温度的影响实际上是可逆的。然而，在这个恢复期间，釉原蛋白的分泌未达到最初在第一天于生理温度下培养的外植体第一天所发现的高水平。从所研究的四个温度得出结论，体外釉质基质沉积的最佳温度为37℃。在此温度下，釉质生物合成及其分泌水平较高。降低温度会减缓代谢，且无明显有害影响。当培养温度恢复到生理水平（37℃）时，牙胚外植体在体外的正常发育得以恢复。因此，对于在任何再植入之前临时储存牙胚外植体，我们建议温度为6℃。
