Kronmiller J E, Beeman C S, Nguyen T, Berndt W
Department of Orthodontics, School of Dentistry, Oregon Health Sciences University, Portland 97201, USA.
Arch Oral Biol. 1995 Jul;40(7):645-52. doi: 10.1016/0003-9969(95)00015-h.
Endogenous retinoids are present in the embryonic mouse mandible and reach a concentration peak immediately before the formation of the dental lamina. Because exogenous retinoids alter the pattern of the dental lamina and the expression of epidermal growth factor mRNA (a transcript necessary for initiation of odontogenesis), the role of retinoic acid in the initiation of odontogenesis was studied here. Citral (3,7-dimethyl-2,6-octadienal), a known inhibitor of retinoic acid synthesis, was used to block the endogenous synthesis of retinoic acid in the mouse embryonic mandible before the formation of the dental lamina (gestational day 9). A 24-h exposure to citral totally blocked tooth formation in 7/10 mandibles. Reductions of endogenous retinoic acid concentrations were confirmed by high-performance liquid chromatography. Tooth formation was restored by simultaneous treatment with all-trans retinoic acid or 9-cis retinoic acid during the citral exposures (first 24 h of culture). Endogenous retinoic acid is necessary for the initiation of odontogenesis.
内源性类视黄醇存在于胚胎期小鼠的下颌骨中，并在牙板形成前即刻达到浓度峰值。由于外源性类视黄醇会改变牙板的形态以及表皮生长因子mRNA（牙胚发生起始所必需的转录本）的表达，因此本文研究了视黄酸在牙胚发生起始过程中的作用。柠檬醛（3,7 - 二甲基 - 2,6 - 辛二烯醛）是一种已知的视黄酸合成抑制剂，在牙板形成前（妊娠第9天）用于阻断小鼠胚胎下颌骨中视黄酸的内源性合成。对柠檬醛进行24小时的暴露处理后，10个下颌骨中有7个完全阻断了牙齿形成。通过高效液相色谱法证实了内源性视黄酸浓度的降低。在柠檬醛暴露期间（培养的前24小时），同时用全反式视黄酸或9 - 顺式视黄酸进行处理可恢复牙齿形成。内源性视黄酸是牙胚发生起始所必需的。
