Changes of Glycoconjugates in Hirschsprung's disease

先天性巨结肠症是由肌间神经节缺失引起的。我们试图研究以糖结合物为主的胚胎微环境，它对未分化的神经母细胞迁移和成熟起着重要的作用。用16种凝集素(ConA、RCA-1、WGA、PNA、SBA、UEA-1、DBA、LCA、PHA-L、DSA、GS-1、VVA、Mpa、BPA、MAA和PSA)对15~21日龄大鼠结肠远端奥尔巴赫神经丛的凝集素结合模式进行了光镜和电子显微镜观察。随着奥尔巴赫神经丛的分化，ConA在孕19天后结合强度增加，而DSA、MPA和RCA-1在妊娠17天后随着奥尔巴赫神经丛的出现而增强。在电子显微镜下，DSA结合部位主要定位于神经细胞的质膜、高尔基体和核膜。在轴膜、神经细胞突起的质膜、雪旺细胞及其周围的平滑肌细胞中也有阳性表达。N-糖酶消化试验表明N-类低聚糖在奥尔巴赫神经丛的形成过程中起重要作用。在先天性巨结肠症中，DSA、RCA-1和WGA在无神经节段的平滑肌层比在正常神经节段的平滑肌层染色更强。这一发现提示，N-连接的寡糖可能在先天性巨结肠症的奥尔巴赫神经丛发育阶段发生了异常。

Hirshsprung's disease is known to be caused by the absence of myenteric ganglia. We attempted to study the embryonic microenvironment which is mainly constituted by glycoconjugates and play an important role for undifferenciated neuroblasts to migrate and maturate. We applied lectin staining to observe the changes of glyoconjugates in the colon during development and in the colon of Hirschsprung's disease.The lectin binding patterns in Auerbach's plexus of the distal portions of the rat colon from 15- to 21-day-old fetuses, newborns, and adults were examined by light and electron microscopy using sixteen different lectins (ConA, RCA-1, WGA, PNA, SBA, UEA-1, DBA, LCA, PHA-L, DSA, GS-1,VVA, MPA, BPA, MAA and PSA ). ConA was shown to increase in their binding after day 19 of gestation with differenciation of Auerbach's plexus, while DSA, MPA, and RCA-1 increased their staining intensity after day 17 of gestation in accordance with the appearance of Auerbach's Plexus. Under electron microscopy, DSA binding sites were localized mainly in the plasma membrane, Golgi apparatus, and nuclear membrane of nerve cells. Positivities were also observed in the axolemma and in the plasma membrane of nerve cell processus, Schwann cells and their surrounding smooth muscle cells. N-glycanase digestion test suggested that N-liked oligosaccbarides play an important role in the development of the Auerbach's plexus.In Hirschsprung's disease, DSA, RCA-1 and WGA were stained stronger in the smooth muscle layer of the aganglionic segment than in that of the normo-ganglionic segment. This finding suggested that N-linked oligosaccharides may have been abnormal at the developmental stage of Auerbach's plexus in Hirschsprung's disease.