先天性腭裂形成中胚胎腭器官的电镜观察

Electron Microscopic Study of the Embryonic Palate during Cleft Palate Formation

背景与目的:建立先天性腭裂模型观察其形成过程中胚胎腭突细胞的超微结构改变。材料与方法:于NIH雌性小鼠受孕第12.5d(GD12.5)通过腹腔注射磷酸地塞米松(50mg/kg)诱发NIH小鼠胚胎先天性腭裂模型,同时设正常对照组注射生理盐水相同条件下饲养。实验组和对照组母鼠分别于GD13.5、GD14.5、GD15.5脱颈处死,剖腹取出胎鼠,切取胎鼠头部制作光镜和电镜样本,采用扫描电镜和透射电镜观察胚胎腭发育及先天性腭裂形成过程中腭突细胞的超微结构。结果:随着胚胎发育,对照组腭突双侧裂隙逐渐变小,上皮基底膜破坏,腭突中嵴上皮细胞(MEE)细胞核染色质呈块状并边集,并可见上皮细胞内出现分泌物质,胚腭间充质细胞(EPM)细胞之间基质丰富,胚胎GD15.5腭突完全融合;实验组腭突生长缓慢,体积较同期对照组小,随着腭突的发育,腭突表层MEE细胞仍然连接紧密,基底膜完整,上皮细胞多层化,细胞表面出现纤毛,EPM细胞之间基质较少,在GD15.5形成裂隙。结论:地塞米松作用后胚胎腭突细胞的正常发育分化受到影响,从而导致腭裂形成。

BACKGROUND AND AIM： To observe the ultrastructure of embryonic palate cells during cleft palate formation using the model of congenital cleft palate. MATERIALS AND METHODS： The model of congenital cleft palate was induced in NIH mice by intraperitoneaL injection of dexamethasone on GD12.5. The control group was raised under the same condition except the injection of dexamethasone. The mice was sacrificed by cervical dislocation on GD13.5, GD14.5 and GD15.5. The fetal mice were removed and the heads were cut for light and electron microscopic studies.The embryonic palate and the palatal cells were examined by SEM and TEM during the process of the palate development and congenital cleft palate formation. RESULTS： In the control group, with the embryonic development, the cleft was diminished, basal epithelial membrane was broken down, pieces of nuclear chromatin became marginated, excretion appeared in the MEE cell, the matrix was abundant between EPM cells, palatine shelves were fused completely on GD15.5. In the experimental group, palatine shelf grew slowly, and was smaller than the control group at the same time point, MEE cells on the palatine shelf surface were connected tightly yet with the development of palatine shelves, basal membrane remained intact, epithelial cell became multiplayer, cilia appeared on the cell surface, the matrix was less between EPM cells, the cleft was formed on GD15.5. CONCLUSION： The development and differentiation of embryonic palatal cells were affected after being exposed to dexamethasone, which was associated with cleft palate formation.