先天性食管闭锁并气管食管瘘的早期胚胎学研究

目的利用阿霉素诱导制作食管闭锁并气管食管瘘（esophageal atresia and tracheoesophageal fistula，EA-TEF）大鼠模型，探讨胚胎发育中气管、食管分化异常的发生机制及可能的影响因素。方法明确孕龄的SD雌性孕鼠9只，随机分为正常组2只及模型组7只，模型组于E6～E9d每日腹腔注射2mg／kg阿霉素，正常组不注射。正常组于E11．5、E12．5d，模型组于E11．5、E12．5、E13．5d取材。进行HE及PAS染色，成纤维细胞生长因子7、10（fibroblast growth factor7，FGF7，10）免疫组化染色。留1只模型组孕鼠于E21d处死，体式镜下解剖。结果①正常对照组：HE染色可见到11．5d肺芽萌出，12．5d时可见气管、食管分离，在气管、食管分离处的前肠壁内有大量的凋亡小体。PAS染色及FGF7、10免疫组化染色可见前肠背侧半及食管为阴性，前肠腹侧半及气管部分为阳性；②模型组：HE染色11．5d未见明显肺芽萌出，12．5d可见瘘管与两侧支气管类似三分叉结构，在几乎相同水平发出。PAS染色及FGF7、10免疫组化染色可见瘘管组织阳性染色，近段前肠可见喉气管憩室以远的腹侧半为阳性。结论对正常大鼠及阿霉素致畸动物模型早期胚胎学的观察得出以下结论：①正常气管、食管的分隔可能与局部细胞的凋亡有关；②气管、食管的正常分隔可能为前肠正常发育的必要条件；③FGF7、10在模型组TEF中表达，表明可能存在间充质细胞的异常，产生异常的信号因子导致TEF。

The embryological changes of the esophagus and trachea in congenital esophageal atresia and tracheo-esophageal fistula

Objective To describe the dysmorphogenetic process leading to esophageal atresia and tracheoesophageal fistula (EA-TEF) in rats. Methods Time-dated pregnant, Sprague-Dawley rats were injected with Adriamycin (2 mg/kg intraperitoneally) in days 6 to 9 of gestatioa Control animals were given nothing. Embryos were recovered on gestational days 11.5 to 13.5 at 1-day interval and nearly at full term (21 days). The immature embryos were sectioned serially and stained with H&E, PAS, or immunohistochemical staining for fibroblast growth factor 7,(FGF7,10). The 21-day embryos were dissected. Results Control: Embryos on day 11.5 had only one foregut tube, and a couple of lung buds started to arise from the ventral surface of the foregut. On day 12.5, the foregut had divided into the esophagus and trachea. Apoptosis was evident in control embryos in the region in which tracheoesophageal separation occurred on day 12.5. The ventral part of the common foregut and the trachea were positive for PAS. The dorsal part of the common foregut and the normal esophagus were negative for PAS. FGF7, 10 were expressed on the places where the PAS staining were positive. Experimental: Embryos on day 12.5, the foregut remained a single tube. The couple of lung buds had risen as normal ones'. Besides the ventral part of the common foregut and the trachea, the fistula was positive for PAS. The distal fistula was given off around where the trachea raised in the experimental embryos, all above the bifurcatioa FGF7, 10 were expressed on the places where the PAS staining were positive. Conclusions The separation of the foregut may be due to apoptosis. It is essential for the normal development of esophagus to correct separation of the foregut. The improper FGF7, 10 expression on the fistula indicates that the mesenchyme around the fistula is abnormal, which might induce the production of the TEF.