Spatiotemporal Expression of Cdx4 in the Developing Anorectum of Rat Embryos with Ethylenethiourea-Induced Anorectal Malformations
Spatiotemporal Expression of Cdx4 in the Developing Anorectum of Rat Embryos with Ethylenethiourea-Induced Anorectal Malformations
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Cdx4在亚乙基硫脲所致肛门直肠畸形大鼠胚胎肛门直肠发育中的时空表达
DOI：
10.1159/000365965
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发表时间：
2014-01-01
影响因子：
2.7
通讯作者：
Bai, Yu Zuo
中科院分区：
文献类型：
--
作者：
Tang, Xiao Bing;Zhang, Jin;Bai, Yu Zuo
目的：本研究旨在检测Cdx4（尾型同源盒基因-4）在正常和乙烯硫脲（ETU）诱导的肛肠畸形（ARM）胚胎肛肠发育过程中的表达，以确定Cdx4在ARM发病中的可能作用。材料与方法：在大鼠胚胎妊娠第10天（GD10）用ETU诱导ARM。然后进行剖宫产来获取胚胎。Cdx4在GD13 ~ GD16期正常大鼠胚胎（n = 354）和ARM胚胎（n = 378）中的时空表达情况。结果：免疫组化和免疫荧光染色显示，正常胚胎GD13上泄殖腔上皮广泛表达Cdx4。在GD14时，cdx4阳性细胞集中在后肠。GD15时，肛门膜对Cdx4持续免疫反应。GD16时，肛门上皮可见cdx4标记细胞。在ARM胚胎中，泄殖腔、尿直肠隔（URS）和肛肠上皮Cdx4呈阴性或微弱。在正常胚胎组，Western blot和实时逆转录加聚合酶链反应显示，Cdx4蛋白和mRNA的表达在发育中的后肠从GD13到GD16中呈现时间依赖性变化。一旦泌尿外科在GD15将泄殖腔分为原始直肠和泌尿生殖窦（UGS）， Cdx4的表达就开始下降。此外，在GD13 ~ GD15期间，ARM组Cdx4表达水平显著低于正常组（p < 0.05）。结论：在ARM胚胎中，Cdx4的时空表达在GD13至GD16的肛肠形态发生过程中存在不平衡。这表明ETU可能导致Cdx4表达下调。因此，Cdx4在泄殖腔分离进入原始直肠和UGS时的下调可能与ARM的发展有关。
Purpose: The aim of this study was to determine the expression of Cdx4 (caudal-type homeobox gene-4) during anorectal development in normal and ethylenethiourea (ETU)-induced anorectal malformation (ARM) embryos with a view to establishing the possible role of Cdx4 in ARM pathogenesis. Materials and Methods: ARM was induced by ETU on the 10th gestational day (GD10) in rat embryos. Cesarean deliveries were then performed to harvest the embryos. Spatiotemporal expression of Cdx4 was evaluated in normal rat embryos (n = 354) and ARM embryos (n = 378) from GD13 to GD16. Results: Immunohistochemical staining and immunofluorescence revealed that, in normal embryos, Cdx4 expression was extensively detected on the epithelium of the cloaca on GD13. On GD14, the Cdx4-positive cells were intensively detected on the hindgut. On GD15, the anal membrane was constantly immunoreactive to Cdx4. On GD16, Cdx4-labeled cells were observed on the epithelium of the anus. In the ARM embryos, the epithelium of the cloaca, urorectal septum (URS) and anorectum was negative or faint for Cdx4. In the normal embryo group, Cdx4 protein and mRNA expression showed time-dependent changes in the developing hindgut from GD13 to GD16 on Western blot and real-time reverse transcription plus polymerase chain reaction. Once the URS divided the cloaca into the primitive rectum and urogenital sinus (UGS) on GD15, Cdx4 expression began to decrease. In addition, the expression level of Cdx4 in the ARM group from GD13 to GD15 was significantly lower than that in the normal group (p < 0.05). Conclusions: In ARM embryos, an imbalance in the spatiotemporal expression of Cdx4 was noted during anorectal morphogenesis from GD13 to GD16. This suggests that ETU may cause downregulation of Cdx4 expression. Downregulation of Cdx4 at the time of cloacal separation into the primitive rectum and UGS might thus be related to the development of ARM.