Sunderman F W, Plowman M C, Hopfer S M
Department of Laboratory Medicine, University of Connecticut School of Medicine, Farmington 06030.
Ann Clin Lab Sci. 1991 Nov-Dec;21(6):381-91.
The embryotoxicity and teratogenicity of cadmium chloride (CdCl2) were tested by the FETAX (Frog Embryo Teratogenesis Assay: Xenopus) procedure in the South African frog, Xenopus laevis. In five assays, groups of Xenopus embryos were grown in media that contained CdCl2 at concentrations ranging from 0.75 to 56 mumol per L; control groups were incubated in the same medium without added CdCl2. The exposures to CdCl2 were begun at the blastula stage (five hours post-fertilization) and were terminated 96 hours later (101 hours post-fertilization). The embryos were counted, fixed in formalin, and examined by microscopy to score malformations and measure head-to-tail lengths. In control groups, greater than or equal to 95 percent of the embryos survived at 101 hours post-fertilization, and the incidence of malformations was less than or equal to 7 percent. In Cd(2+)-exposed groups, there was concentration-dependent mortality, and the embryos showed a concentration-related pattern of malformations, including gut malrotation, ocular anomalies, bent notochord, misshapen dorsal fin, facial dysplasia, cardiac deformities, and dermal blisters. Other abnormalities, not categorized as malformations, included stunted growth and hypopigmentation. The minimum concentration of CdCl2 that inhibited growth (MCIG) was 18 mumol per L. The median embryolethal concentration (LC50) of CdCl2 was 32 (SE +/- 4) mumol per L; the median teratogenic concentration (EC50) was 3.7 (SE +/- 1) mumol per L; the teratogenic index (TI = LC50/EC50) was 8.6. This study demonstrates that CdCl2 is teratogenic for Xenopus laevis and provides a standardized experimental model for studies of the molecular mechanisms of cadmium teratogenesis.
采用FETAX（非洲爪蟾胚胎致畸试验）方法，在南非爪蟾（非洲爪蟾）中测试了氯化镉（CdCl₂）的胚胎毒性和致畸性。在五项试验中，将非洲爪蟾胚胎分组培养于含有浓度范围为0.75至56 μmol/L CdCl₂的培养基中；对照组在不添加CdCl₂的相同培养基中孵育。CdCl₂暴露从囊胚期（受精后5小时）开始，96小时后（受精后101小时）结束。对胚胎进行计数，用福尔马林固定，并通过显微镜检查以对畸形进行评分并测量头尾长度。在对照组中，受精后101小时时大于或等于95%的胚胎存活，畸形发生率小于或等于7%。在Cd²⁺暴露组中，存在浓度依赖性死亡率，胚胎呈现出与浓度相关的畸形模式，包括肠道旋转不良、眼部异常、弯曲的脊索、畸形的背鳍、面部发育异常、心脏畸形和皮肤水泡。其他未归类为畸形的异常包括生长发育迟缓以及色素沉着不足。抑制生长的CdCl₂最低浓度（MCIG）为18 μmol/L。CdCl₂的半数胚胎致死浓度（LC50）为32（标准误±4）μmol/L；半数致畸浓度（EC50）为3.7（标准误±1）μmol/L；致畸指数（TI = LC50/EC50）为8.6。本研究表明CdCl₂对非洲爪蟾具有致畸性，并为镉致畸分子机制的研究提供了标准化实验模型。
