Pratt R M, Goulding E H, Abbott B D
Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
J Craniofac Genet Dev Biol. 1987;7(3):205-17.
Clinical observations have demonstrated that isotretinoin (13-cis-retinoic acid; cis-RA) is a human teratogen causing primarily heart and craniofacial malformations. Isotretinoin exposure to the early postimplantation mouse embryo in culture results in specific defects in craniofacial development that may be due to an interference in the early migration of cranial neural crest (CNC) cells [Goulding and Pratt, 1986]. The present study was designed to test this hypothesis by examining the migration of these cells in whole embryo culture. Day 8 CD-1 mouse embryos were cultured for 6-48 hr in the presence or absence of cis-RA at 2 X 10(-6) to 2 X 10(-5) M. Embryos either were fixed for light microscopy using Nichols' method for localization of CNC cells or were processed for scanning and transmission electron microscopy. At the light microscopic level, CNC cells in the mid-brain region of control embryos had migrated to the region of the first and second visceral arches after 6 hr in culture. Cis-RA interfered with this migration; CNC cells in treated embryos either did not leave the neuroepithelium (NE) or were aggregated near the NE. Autoradiographic studies indicated that cis-RA did not affect the overall viability or DNA synthesis of the CNC cells. However, at the TEM level, there was a dramatic increase in the number of cellular blebs in the CNC cells. Our results demonstrate a direct effect of 13-cis-RA on the CNC cells and suggest that this effect is due to alterations in the cell surface.
临床观察表明，异维甲酸（13 - 顺式维甲酸；顺式 - RA）是一种人类致畸剂，主要导致心脏和颅面部畸形。在培养中，将异维甲酸作用于植入后早期的小鼠胚胎，会导致颅面部发育出现特定缺陷，这可能是由于颅神经嵴（CNC）细胞早期迁移受到干扰所致[古尔丁和普拉特，1986年]。本研究旨在通过检测全胚胎培养中这些细胞的迁移来验证这一假设。将第8天的CD - 1小鼠胚胎在存在或不存在2×10⁻⁶至2×10⁻⁵M顺式 - RA的情况下培养6 - 48小时。胚胎要么使用尼科尔斯法固定用于光镜观察以定位CNC细胞，要么进行扫描和透射电子显微镜处理。在光镜水平，培养6小时后，对照胚胎中脑区域的CNC细胞已迁移至第一和第二内脏弓区域。顺式 - RA干扰了这种迁移；处理过的胚胎中的CNC细胞要么未离开神经上皮（NE），要么聚集在NE附近。放射自显影研究表明，顺式 - RA不影响CNC细胞的总体活力或DNA合成。然而，在透射电镜水平，CNC细胞中的细胞泡数量显著增加。我们的结果证明了13 - 顺式 - RA对CNC细胞有直接作用，并表明这种作用是由于细胞表面的改变所致。
