While the correlation between diabetes during pregnancy and birth defects is well-established, how hyperglycemia causes developmental abnormalities remains unclear. In this study, we developed a novel “hyperglycemic” chicken embryonic model by administrating various doses of glucose to fertilized eggs at embryonic stages HH16 or HH24. When the embryos were collected at HH35, the LD50 was 1.57 g/Kg under HH16 treatment and 0.93 g/Kg under HH24 treatment, indicating that “hyperglycemic” environments can be lethal for the embryos. When exposed to a dose equal to or higher than 1 g/Kg glucose at HH16 or HH24, more than 40% of the surviving chicken embryos displayed heart defects and/or limb defects. The limb defects were associated with proliferation defects of both the wing and leg buds indicated by reduced numbers of p-H3S10 labeled cells. These limb defects were also associated with ectopic apoptosis in the leg bud and expression changes of key apoptotic genes. Furthermore, glucose treatment induced decreased expression of genes involved in Shh-signaling, chondrogenesis, and digit patterning in the limb bud. In summary, our data demonstrated that a high-glucose environment induces congenital heart and limb defects associated with disrupted cell proliferation and apoptosis, possibly through depressed Shh-signaling.

虽然妊娠期糖尿病与先天缺陷之间的相关性已经确立，但高血糖如何导致发育异常仍不清楚。在这项研究中，我们通过向处于 HH16 或 HH24 胚胎阶段的受精卵施用不同剂量的葡萄糖，开发了一种新型的“高血糖”鸡胚胎模型。在 HH35 收集胚胎时，HH16 处理下的 LD50 为 1.57 g/Kg，HH24 处理下为 0.93 g/Kg，表明“高血糖”环境对胚胎可能是致命的。当在 HH16 或 HH24 暴露于等于或高于 1 g/Kg 葡萄糖的剂量时，超过 40% 的存活鸡胚胎显示出心脏缺陷和/或四肢缺陷。肢体缺陷与翼芽和腿芽的增殖缺陷相关，p-H3S10 标记的细胞数量减少。这些肢体缺陷还与腿芽中的异位细胞凋亡和关键细胞凋亡基因的表达变化有关。此外，葡萄糖治疗会导致肢体芽中参与 Shh 信号传导、软骨形成和手指图案形成的基因表达降低。总之，我们的数据表明，高糖环境可能通过抑制 Shh 信号传导，诱发与细胞增殖和凋亡中断相关的先天性心脏和四肢缺陷。