The ETU - administration group had 15 pregnant rats while the saline -administration group had 5. At the 20th day of gestation, fetal surgery was performed to expose the rectum or the rectal pouch and then injected 5% fluorogold (FG).

• 对照组5只孕鼠，注入等量生理盐水。 孕20天时，进行胎儿外科手术，通过显微注射方法，将5%25荧光金（luorogold，FG）注射人正常胎鼠直肠壁及畸形胎鼠的直肠盲端肌层内。