Ambroso J L, Stedman D B, Elswick B A, Welsch F
Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709-2137, USA.
Teratology. 1998 Dec;58(6):231-40. doi: 10.1002/(SICI)1096-9926(199812)58:6<231::AID-TERA4>3.0.CO;2-X.
Cell death was analyzed in neurulating mouse embryos after in vivo doses of 2-methoxyethanol (2-ME) that produce anterior neural tube defects. Characterization of 2-ME-induced cell death was performed by evaluating: (1) vital fluorochrome staining in whole embryos applying confocal laser scanning microscopy; (2) characteristics of cell debris in conventional histological sections revealed by light microscopy; and (3) Apoptag in situ immunohistochemical staining for apoptosis using light microscopy. Methods for quantification of cell death identified by these three techniques were explored using computerized image analysis. Physiological cell death in control embryos primarily occurred in the neural crest region during neural fold elevation. Embryos exposed to 2-ME had expanded areas of cell death in the neural crest and also new areas of cell death in medial regions of the anterior neural tube. Both physiological and 2-ME-induced embryonic cell death had morphological, immunohistochemical, and fluorochrome staining characteristics of apoptosis. When fluorescence data from confocal microscopic analysis of vital fluorochrome-stained embryos were analyzed, a dose-dependent increase was found in embryos exposed to 2-ME. Similar results were obtained when cell death was analyzed in either conventional histological sections or sections prepared for immunohistochemical detection of apoptosis. The cell death data obtained in this study correlate with previously observed near-term malformation rates, suggesting that a quantitative relationship exists between 2-ME-induced embryonic cell death and neural tube defects.
在给予能导致前神经管缺陷的体内剂量的2-甲氧基乙醇（2-ME）后，对处于神经胚形成阶段的小鼠胚胎中的细胞死亡情况进行了分析。通过评估以下方面对2-ME诱导的细胞死亡进行了特征描述：（1）应用共聚焦激光扫描显微镜对整个胚胎进行活性荧光染料染色；（2）通过光学显微镜观察常规组织切片中细胞碎片的特征；（3）使用光学显微镜对凋亡进行原位免疫组化染色（Apoptag）。利用计算机图像分析探索了通过这三种技术鉴定细胞死亡的定量方法。对照胚胎中的生理性细胞死亡主要发生在神经褶抬高期间的神经嵴区域。暴露于2-ME的胚胎在神经嵴中有扩大的细胞死亡区域，并且在前神经管内侧区域也出现了新的细胞死亡区域。生理性和2-ME诱导的胚胎细胞死亡均具有凋亡的形态学、免疫组化和荧光染料染色特征。当对活性荧光染料染色的胚胎进行共聚焦显微镜分析的荧光数据进行分析时，发现暴露于2-ME的胚胎中存在剂量依赖性增加。当在常规组织切片或为凋亡免疫组化检测制备的切片中分析细胞死亡时，也获得了类似结果。本研究中获得的细胞死亡数据与先前观察到的近期畸形率相关，表明2-ME诱导的胚胎细胞死亡与神经管缺陷之间存在定量关系。
