Smith D M, Torres R D, Stephens T D
Department of Biological Sciences, Idaho State University, Pocatello 83201, USA.
Teratology. 1996 Sep;54(3):126-34. doi: 10.1002/(SICI)1096-9926(199609)54:3<126::AID-TERA2>3.0.CO;2-1.
Recent studies have demonstrated a link between limb reduction defects and mesonephros removal [Geduspan and Solursh, 1992) Dev. Biol., 151:242-250]. However, there is some question as to whether the limb-reduction defects seen in that study resulted from the removal of mesonephros or from the formation of scar tissue medial to the limb territory. The current study was conducted to test the hypothesis that elimination of the mesonephros without producing scar tissue adjacent to the limb will adversely affect limb morphogenesis. The hypothesis was tested by the insertion of tantalum foil barriers into various levels of the intermediate mesoderm of developing chick embryos to prevent the caudal elongation of the mesonephros. Limb reduction defects were obtained when the mesonephros was prevented from forming caudal to somite 14. No limb defects were seen when a foil barrier was placed into the intermediate mesoderm at the level of somite 21 or 25. Our results support the notion that a signal from the mesonephros is necessary for normal limb development. In addition, it appears that a craniocaudal factor emanating from the mesonephros plays a role in limb development. The limb reduction defects obtained in this study were also compared to the pattern of thalidomide embryopathy in humans. There is a close correspondence between the types of limb reduction anomalies seen with thalidomide and mesonephric blocks and between the severity of defects vs. the timing of thalidomide intake or mesonephric blockage. A model for possible thalidomide embryopathy is presented.
近期研究表明肢体减少缺陷与中肾移除之间存在关联[Geduspan和Solursh，1992年，《发育生物学》，151:242 - 250]。然而，对于该研究中所见的肢体减少缺陷是由中肾移除还是肢体区域内侧瘢痕组织的形成所致，存在一些疑问。进行本研究是为了检验以下假设：在不产生肢体附近瘢痕组织的情况下消除中肾会对肢体形态发生产生不利影响。通过将钽箔屏障插入发育中的鸡胚中间中胚层的不同水平来阻止中肾向尾端延伸，从而对该假设进行了检验。当中肾在第14体节尾侧的形成受到阻止时，出现了肢体减少缺陷。当在第21或25体节水平将箔屏障置于中间中胚层时，未观察到肢体缺陷。我们的结果支持这样一种观点，即来自中肾的信号对于正常肢体发育是必要的。此外，似乎从中肾发出的头尾向因子在肢体发育中起作用。本研究中获得的肢体减少缺陷也与人类沙利度胺胚胎病的模式进行了比较。沙利度胺和中肾阻断所致的肢体减少异常类型之间，以及缺陷严重程度与沙利度胺摄入或中肾阻断时间之间存在密切对应关系。提出了一个关于沙利度胺胚胎病可能机制的模型。
