BACKGROUND Anorectal malformations (ARMs) are common congenital malformations of the terminal digestive tract, but little is known regarding their pathogenesis. Aberrant cell proliferation/apoptosis are believed to be involved in ARMs. However, there are no studies on proliferation/apoptosis-related genes. PURPOSE We aimed to investigate the spatiotemporal expression patterns of two proliferation/apoptosis-related genes (MYC proto-oncogene and tumor protein p53) and explore their potential functions in the hindguts of ethylene thiourea-induced ARMs rat fetuses. METHODS MYC and p53 expression was evaluated using immunohistochemical staining, western blotting, and quantitative real-time polymerase chain reaction (RT-qPCR). Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and p53 costaining were performed to assay the colocalization of apoptotic and p53-expressing cells. RESULTS Rat fetuses with ARMs displayed fusion failure of the urogenital septum and cloacal membrane. In the control group, MYC was persistently expressed from gestational day (GD)14 to GD16 and distributed throughout the hindgut, while p53 was weakly detected in the terminal segment of the urethra and hindgut; in the ARMs group, MYC expression was obviously reduced, while p53 was widely and highly expressed in the urethra and hindgut. Western blotting and RT-qPCR confirmed the decrease in MYC and increase in p53 expression in ARMs. TUNEL and p53 co-staining revealed considerable overlap between apoptotic and p53-expressing cells. CONCLUSION The expression patterns of c-myc and p53 were disrupted in ARMs rat embryos, and the downregulation of c-myc and upregulation of p53 might be related to the development of ARMs at the key time points of ARMs morphogenesis.

中文翻译：

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增生和凋亡因子参与亚乙基硫脲引起的肛门直肠畸形的大鼠胎儿后肠发育。

背景技术肛肠畸形（ARMs）是终末消化道的常见先天性畸形，但对其发病机理知之甚少。异常的细胞增殖/凋亡被认为与ARM有关。但是，尚无关于增殖/凋亡相关基因的研究。目的我们旨在研究两个增殖/凋亡相关基因（MYC原癌基因和肿瘤蛋白p53）的时空表达模式，并探讨它们在乙烯硫脲诱导的ARMs大鼠胎儿后肠中的潜在功能。方法使用免疫组织化学染色，western印迹和定量实时聚合酶链反应（RT-qPCR）评估MYC和p53的表达。进行末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）和p53共染色以检测凋亡细胞和表达p53的细胞的共定位。结果患有ARM的大鼠胎儿表现出泌尿生殖器隔膜和泄殖腔膜融合失败。对照组中，MYC从妊娠第14天到GD16持续表达并分布在整个后肠，而在尿道和后肠的末端部分检测到p53较弱。在ARMs组中，MYC表达明显降低，而p53在尿道和后肠中广泛且高度表达。Western blotting和RT-qPCR证实了ARMs中MYC的减少和p53表达的增加。TUNEL和p53共染色显示凋亡细胞和表达p53的细胞有相当多的重叠。