肛门直肠畸形大鼠泄殖腔胚胎发育过程中细胞凋亡的研究(英文)

Cell apoptosis during the cloacal embryonic development in rats with anorectal malformations

目的肛门直肠正常胚胎发育过程中,细胞凋亡发挥重要作用。该研究调查了肛门直肠畸形(anorectal malformation,ARM)胎鼠泄殖腔胚胎发育过程中细胞凋亡情况,以了解ARM胚胎发育过程中细胞凋亡的作用。方法在胚胎发育的第10天,通过胃管注入乙烯硫脲(125 mg/kg)致畸孕鼠,诱导ARM胚胎。在胚胎发育的第13,13.5,14,15和16天,利用苏木素-伊红和TUNEL染色技术检测正常对照胚胎(n=102)和ARM胚胎(n=147)泄殖腔凋亡细胞的分布。结果对照组胚胎第13天尿直肠隔可见凋亡细胞,随着胚胎发育,尿直肠隔间质内的凋亡细胞逐渐增多;直肠背侧间质可见大量凋亡细胞。胚胎第14天,直肠末端和未来肛门开口处的泄殖腔膜开始出现凋亡细胞。胚胎第15天,尿直肠隔与泄殖腔膜融合,尿直肠隔间质内的凋亡细胞一直向下延伸到融合部位。ARM胎鼠与对照组胎鼠相比,在胚胎发育过程中尿直肠隔间质、直肠背侧间质和泄殖腔膜的凋亡细胞均明显减少。ARM胎鼠尿直肠隔的发育明显延迟,未与泄殖腔膜融合。结论在泄殖腔的胚胎发育过程中,尿直肠隔间质、直肠背侧间质和泄殖腔膜细胞凋亡的异常是导致ARM的原因之一。细胞凋亡的正常调控是保证肛门直肠胚胎期正常发育的关键机制之一。

Objective In the normal embryonic development of anorectum, apoptosis plays an important role. To explore the role of apoptosis in anorectal malformations （ ARM ） , this study investigated cell apoptosis during the cloacal embryonic development in ARM embryos. Methods ARM embryos were induced by intragastric administration of ethylenethiourea （125 mg/kg） for pregnant rats on embryonic day 10 （E10）. The distribution of apoptotic cells in the cloaca was ascertained by hematoxylin and eosin and TUNEL staining in the normal control embryos （n = 102） and ARM embryos （n = 147） on E13, E13.5, E14, E15 and E16, Results On E13, apoptotic cells were detected in the urorectal septum of rat embryos in the control group. With the development of embryos, the number of apoptotic ceils in the mesenchyme of urorectal septum gradually increased and a large number of apoptotic ceils were seen in the dorsal rectal mesenchyme. On E14, apoptotic ceils appeared at the terminal rectum and the dorsal cloacal membrane. On E15, the urorectal septum fused with the cloacal membrane and apoptotic cells in the uroreetal septum mesenchyme continuously extended down to the fusion region. Compared with the control group, apoptotic cells in the urorectal septum, the dorsal rectal mesenchyme and the cloacal membrane of the ARM rat embryos were significantly reduced during the embryonic development. The development of the urorectal septum was delayed and it did not fuse with the cloacal membrane in ARM embryos. Conclusions During the embryonic development of cloaca, abnormal apoptosis in the urorectal septum, the dorsal rectal mesenchyme and the cloacal membrane may be one of the reasons for anorectal malformations. The proper regulation of cell apoptosis may be one of the key mechanisms for normal development of anorectum in the embryonic stage.