Parnell Scott E, Dehart Deborah B, Wills Tiffany A, Chen Shao-Yu, Hodge Clyde W, Besheer Joyce, Waage-Baudet Heather G, Charness Michael E, Sulik Kathleen K
Bowles Center for Alcohol Studies, Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Alcohol Clin Exp Res. 2006 Oct;30(10):1791-8. doi: 10.1111/j.1530-0277.2006.00212.x.
This work was conducted in an effort to establish an oral intake model system in which the effects of ethanol insult that occur during early stages of embryogenesis can be easily examined and in which agents that may modulate ethanol's teratogenicity can be readily tested in vivo. The model system described utilizes the alcohol deprivation effect to obtain teratogenic levels of maternal ethanol intake on days 7 and 8 of pregnancy in C57Bl/6J mice. Ocular defects including microphthalmia and uveal coloboma, which have previously been shown to result from ethanol administered by gavage or via intraperitoneal injection on these days, served as the developmental end point for this study. The ocular defects are readily identifiable and their degree of severity is expected to correlate with concurrently developing defects of the central nervous system (CNS).
Female C57Bl/6J mice were maintained on an ethanol-containing (4.8% v/v) liquid diet for 14 days and then mated during a subsequent abstinence period. Mice were then reexposed to ethanol on days 7 and 8 of pregnancy only. Control as well as ethanol-exposed dams were killed on their 14th day of pregnancy. Fetuses were then weighed, measured for crown rump length, photographed, and analyzed for ocular abnormalities. Globe size, palpebral fissure length, and pupil size and shape were noted for both the right and left eyes of all fetuses and informative comparisons were made.
This exposure paradigm resulted in peak maternal blood alcohol concentrations that ranged from 170 to 220 mg/dL on gestational day (GD) 8. Compared with the GD 14 fetuses from the normal control group, the pair-fed, acquisition controls, as well as the ethanol-exposed fetuses, were developmentally delayed and had reduced weights. Confirming previous studies, comparison of similarly staged control and treated GD 8 embryos illustrated reductions in the size of the forebrain in the latter. Subsequent ocular malformations were noted in 33% of the right eyes and 25% of the left eyes of the 103 GD 14 ethanol-exposed fetuses examined. This incidence of defects is twice that observed in the control groups. Additionally, it was found that the palpebral fissure length is directly correlated with globe size.
The high incidence of readily identifiable ocular malformations produced by oral ethanol intake in this model and their relevance to human fetal alcohol spectrum disorders (FASD) makes this an excellent system for utilization in experiments involving factors administered to the embryo that might alter ethanol's teratogenic effects. Additionally, the fact that early ethanol insult yields ocular and forebrain abnormalities that are developmentally associated allows efficient specimen selection for subsequent detailed analyses of CNS effects in this in vivo mammalian FASD model.
开展本研究旨在建立一种口服摄入模型系统，以便能够轻松检测胚胎发育早期乙醇损伤的影响，并能在体内方便地测试可能调节乙醇致畸性的药物。所描述的模型系统利用酒精剥夺效应，使C57Bl/6J小鼠在妊娠第7天和第8天达到致畸水平的母体乙醇摄入量。先前已证明，在这几天通过灌胃或腹腔注射给予乙醇会导致包括小眼症和脉络膜缺损在内的眼部缺陷，这些眼部缺陷作为本研究的发育终点。眼部缺陷易于识别，并且预计其严重程度与同时发生的中枢神经系统（CNS）缺陷相关。
将雌性C57Bl/6J小鼠维持在含乙醇（4.8% v/v）的液体饮食中14天，然后在随后的禁戒期进行交配。然后仅在妊娠第7天和第8天让小鼠重新接触乙醇。在妊娠第14天处死对照以及乙醇暴露的母鼠。然后对胎儿称重、测量顶臀长度、拍照，并分析眼部异常情况。记录所有胎儿左右眼的眼球大小、睑裂长度以及瞳孔大小和形状，并进行有益的比较。
这种暴露模式导致妊娠第8天母体血酒精浓度峰值在170至220 mg/dL之间。与正常对照组妊娠第14天的胎儿相比，配对喂养的获取对照组以及乙醇暴露的胎儿发育延迟且体重减轻。与先前研究一致，对妊娠第8天处于相似阶段的对照和处理胚胎进行比较，结果显示后者前脑尺寸减小。在所检查的103个妊娠第14天乙醇暴露胎儿中，33%的右眼和25%的左眼出现了随后的眼部畸形。这种缺陷发生率是对照组的两倍。此外，发现睑裂长度与眼球大小直接相关。
该模型中口服乙醇导致的易于识别的眼部畸形发生率高，且与人类胎儿酒精谱系障碍（FASD）相关，这使其成为用于涉及给予胚胎可能改变乙醇致畸作用的因素的实验的极佳系统。此外，早期乙醇损伤产生在发育上相关的眼部和前脑异常这一事实，使得在这个体内哺乳动物FASD模型中能够有效地选择标本，用于随后对CNS效应的详细分析。
