先天性食管闭锁并气管食管瘘的大鼠胚胎学研究

Embryological study of the rat embryos developing congenital esophageal atresia and tracheoesophageal fistula

目的利用阿霉素诱导食管闭锁并气管食管瘘大鼠胚胎模型（adriamycin—induced rat model，ARM）与正常大鼠胚胎作比较，研究气管、食管的正常与异常分化过程，探讨产生食管闭锁并气管食管瘘（esophageal atresia and tracheoesopllageal fistula，EA—TEF）的可能影响因素。方法SD孕鼠12只，随机分为模型组8只及正常组4只。模型组于E6～9d每日腹腔注射阿霉素2mg／kg，正常组不注射。于E10．5～13．5d每天取2只模型组孕鼠及1只正常组孕鼠，剖腹取胚胎．逐个石蜡包埋，做前肠横切片，进行HE染色观察形态学、免疫荧光枪测Shh表达。结果①形态学：模型组胚胎发育较正常组晚，细胞增生较少；多存在异常脊索与前肠背侧接近、相连或融合；②Shh表达：正常组E10．5d表达最明显，随着胚胎天数增大，表达量渐少，呈下降一降表达。模型组表达比正常组弱，无下降性表达。但在有脊索异常分支处表达明显，同时前肠表达明显。结论EA-TEF的发生可能与脊索的异常相关。脊索异常可能使Shh表达部位及水平异常，在EA-TEF的发牛中发挥重要作用。

Objective To investigate the embryological development and Sonic Hedgehogs （Shh） expression in an adriamycin rat model（ARM） of esophageal atresia and traeheoesophageal fistula（EA-TEF）. Methods Twelve timed pregnant, Sprague-Dawley rats were randomly divided into two groups： ARM group （n = 8） and normal control group （n = 4）. The rats of ARM group were intraperitoneally administrated with adriamycin （2 mg/kg） on gestational days 6 to 9 （E6-E9）. From E10. 5 to E13. 5, the embryos of 2 ARM rats and i normal control rat were harvested by caesarean section every day. The embryos were processed and serially sectioned in the transverse planes. The slides were stained with H＆E staining. Shh was detected by immunofluoreseence staining. ResultsThe ARM enbryos displayed a reduction in cell proliferation and delayed embryological development compared to the normal control embryos. Most of the ARM embryos had ectopic notochord which approached to, atta ched to or even fused with foregut. In normal control embryos, the highest expression of Shh in foregut occurred on E10. 5, then it decreased with the gestational age. Compared to the normal control embryos, the Shh expression in ARM embryos was lower, and it didn＇t show the tendency to decrease with the gestational age. The expression of Shh in ectopic notochord and foregut was prominent in ARM embryos. Conclusions The abnormal notochord development may contribute to the embryological development of EA TEF. The ectopic expression and the absence of down-regulation of Shh may play an important role in the embryological development of EA-TEF.