YuZuo Bai1, Hui Chen, Zheng Wei Yuan, WeiLin Wang. 1. Department of Pediatric Surgery, The Second Affiliated Hospital, China Medical University, Shenyang, People's Republic of China.
Abstract
BACKGROUND: The embryologic and pathologic aspect of anorectal malformation (ARM) remains poorly understood. There is no universally accepted theory to explain anorectal embryology and the abnormal development that produces ARM. The aim of this study was to observe the developmental processes of anorectum in rats and to explore the abnormal embryonic development that leads to ARM. METHODS: Rat embryos with ARM were obtained by treating pregnant rats with administration of ethylenethiourea (ETU). Normal rat embryos and embryos with ARM from gestational days 12.5 to 20 were sectioned serially and sagittally and stained with H & E. The relevant structure including cloaca and urorectal septum (URS) were examined in a temporospatial sequence. RESULTS: Characteristics of anorectum development in ARM rat embryos treated by ETU were as follows: (1) URS never fused with cloaca membrane. (2) Dorsal cloacal membrane was maldeveloped. (3) Cloacal configuration was abnormal. (4) Tail groove never appeared. All type of ARM was the rectourethal fistula and common cloaca in ETU-treated rat embryos and was discernible on gestation day 16. CONCLUSIONS: Absence of the tail groove and maldevelopment of the dorsal cloacal membrane, cloacal configuration, and urorectal septum are likely to be responsible for the formation of ARM. Failure of fusion of the URS with cloacal membrane is the immediate reason for rectourethral fistula or common cloaca in ETU-treated rats.
BACKGROUND: The embryologic and pathologic aspect of anorectal malformation (ARM) remains poorly understood. There is no universally accepted theory to explain anorectal embryology and the abnormal development that produces ARM. The aim of this study was to observe the developmental processes of anorectum in rats and to explore the abnormal embryonic development that leads to ARM. METHODS:Rat embryos with ARM were obtained by treating pregnant rats with administration of ethylenethiourea (ETU). Normal rat embryos and embryos with ARM from gestational days 12.5 to 20 were sectioned serially and sagittally and stained with H & E. The relevant structure including cloaca and urorectal septum (URS) were examined in a temporospatial sequence. RESULTS: Characteristics of anorectum development in ARM rat embryos treated by ETU were as follows: (1) URS never fused with cloaca membrane. (2) Dorsal cloacal membrane was maldeveloped. (3) Cloacal configuration was abnormal. (4) Tail groove never appeared. All type of ARM was the rectourethal fistula and common cloaca in ETU-treated rat embryos and was discernible on gestation day 16. CONCLUSIONS: Absence of the tail groove and maldevelopment of the dorsal cloacal membrane, cloacal configuration, and urorectal septum are likely to be responsible for the formation of ARM. Failure of fusion of the URS with cloacal membrane is the immediate reason for rectourethral fistula or common cloaca in ETU-treated rats.
Authors: Tao Zhang; Hai Lan Zhang; Da Jia Wang; Xiao Bing Tang; Hui Min Jia; Yu Zuo Bai; Zheng Wei Yuan; Wei Lin Wang Journal: Int J Colorectal Dis Date: 2010-08-05 Impact factor: 2.571
Authors: Cindy C Tai; Frederic G Sala; Henri R Ford; Kasper S Wang; Changgong Li; Parviz Minoo; Tracy C Grikscheit; Saverio Bellusci Journal: J Surg Res Date: 2009-05-08 Impact factor: 2.192
Authors: Tao Zhang; Yu Zuo Bai; Da Jia Wang; Hui Min Jia; Zheng Wei Yuan; Wei Lin Wang Journal: Int J Colorectal Dis Date: 2009-04-22 Impact factor: 2.571