van Maele-Fabry G, Gofflot F, Picard J J
Laboratory of Developmental Genetics, Catholic University of Louvain, Louvain-la-Neuve, Belgium.
Teratology. 1996 Jan;53(1):10-20. doi: 10.1002/(SICI)1096-9926(199601)53:1<10::AID-TERA2>3.0.CO;2-D.
The embryotoxic and dysmorphogenic effects of mercuric chloride (HgCl2) have been studied in mouse embryos cultured in vitro. In addition, the alterations induced in the developing branchial nerves and ganglia were analyzed. Mouse embryos with 6-8 pairs of somites were exposed for 26 hr to increasing concentrations (0, 12.5, 25, 50 microM) of HgCl2. After this period, a first set of embryos was removed and a second set of embryos transferred to culture medium without HgCl2 and remained in culture for an additional 22 hr. Both sets of embryos were examined for (1) survival, (2) presence of external dysmorphogenesis, (3) growth, and (4) differentiation. Dose-related alterations of these parameters were observed. The main target was the cephalic neural tube (mainly the forebrain), but several other systems were also affected (e.g., the turning of the embryos, the optic system). The 48-hr cultured embryos were immunostained using a monoclonal antineurofilament antibody to visualize defects in the development of branchial nerves and ganglia. HgCl2 induced a pronounced retardation in the differentiation of ganglion/nerve V and a slight retardation in the differentiation of ganglia/nerves VII and IX. The ganglia/nerves VIII and X were not retarded. In addition, hight percentages of abnormalities of ganglion/nerve V and fusions between ganglia/nerves IX and X were observed in these embryos. Disorganized fibers between ganglia/nerves VII-VIII and IX and between ganglia/nerves IX and X were also more frequently observed. At the highest concentration, asymmetric defects were induced by HgCl2 with a more pronounced effect observed on the right side of the embryos. These results demonstrate the usefulness of this approach in evaluating the susceptibility of the developing branchial nerves to the adverse effects of developmental toxicants.
已在体外培养的小鼠胚胎中研究了氯化汞（HgCl₂）的胚胎毒性和致畸作用。此外，还分析了发育中的鳃神经和神经节所诱导的变化。将具有6 - 8对体节的小鼠胚胎暴露于浓度递增（0、12.5、25、50微摩尔）的HgCl₂中26小时。在此之后，取出第一组胚胎，将第二组胚胎转移至不含HgCl₂的培养基中，并再培养22小时。对两组胚胎进行了以下检查：（1）存活情况，（2）外部致畸情况，（3）生长情况，以及（4）分化情况。观察到这些参数与剂量相关的变化。主要靶器官是头部神经管（主要是前脑），但其他几个系统也受到影响（例如，胚胎的扭转、视觉系统）。使用单克隆抗神经丝抗体对培养48小时的胚胎进行免疫染色，以观察鳃神经和神经节发育中的缺陷。HgCl₂导致神经节/神经V的分化明显延迟，神经节/神经VII和IX的分化略有延迟。神经节/神经VIII和X没有延迟。此外，在这些胚胎中观察到神经节/神经V的异常以及神经节/神经IX和X之间融合的高比例情况。在神经节/神经VII - VIII与IX之间以及神经节/神经IX与X之间，纤维紊乱的情况也更频繁地被观察到。在最高浓度下，HgCl₂诱导了不对称缺陷，在胚胎右侧观察到的影响更为明显。这些结果证明了这种方法在评估发育中的鳃神经对发育毒物不良反应的易感性方面的有用性。
