胎儿发育过程中食管上皮糖复合物的改变

DISTRIBUTION AND CHANGES OF GLYCOCONJUGATES IN FETAL ESOPHAGEAL EPITHELIUM: A HISTOCHEMICAL STUDY USING LECTINS

采用十种生物素化凝集素 U EA- I、 DBA、 PSA、 BSL、 PNA、 L CA、 RCA- I、SBA、 Con A及 WGA分别对 8W、1 4 W、 2 0 W 2 8W及 32 W的人胎儿食管上皮进行研究 ,以确定胎儿食管上皮在发育过程中凝集素的结合位点以及结合方式随年龄的变化。结果提示 ,BSL、 RCA- I、 WGA的染色强度及特性不受年龄影响 ,而与之相对应 ,U EA - 1在除 2 0 W以外的食管上皮显色 ;含α- D- Glc NAc的糖复合物 (DBA受体 )只在 2 0 W表达 ;含α- D- man/α- D- Glc的糖复合物 (PSA受体 )则只出现于 32 W;Con A受体虽在胎儿食管上皮各年龄组都表现阳性反应 ,但在 2 8W 时受体在上皮各层细胞中的分布方式及染色强度出现了有意义的变化 ,即腔面细胞染色阴性 ,中层细胞染色强阳性 ,基底细胞弱阳性 ,而在其他时间腔面反应强阳性 ,中层中等阳性 ,基底弱阳性 ;PNA、SBA及 L CA在各年龄组均呈阴性反应。这些结果表明 ,在胎儿食管上皮发育过程中存在着多个凝集素结合位点 ,含 α- L- Fucose、 α- D- Gal NAc、α- D- Man/ α- D- Glc残基的糖复合物在分布方式和 /或量上存在着发育相关性改变 ,即糖复合物的改变具有阶段性。总之 ,本实验资料提示 ,胎儿食管上皮在发育过程中表现出不同的结合位点 ,RCA- 、 BSL、

Biotinylated lectins:UEA Ⅰ, RCA Ⅰ, DBA, PSA, PNA, BSL, LCA, WGA, ConA AND SBA were used as probes to identify lectin binding sites and to determine if lectin binding patterns change with age in the developing of human fetal esophageal epithelium (8W, 14W, 20W, 28W and 32W). Lectin binding was visualized in fomalin fixed and avidin peroxidase staining procedures. Staining patterns and intensity for BSL, RCA Ⅰ, and WGA were not affected by fetal age In contrast, UEA Ⅰ showed positive reactivity during the development period except for 20W; DBA and PSA showed positive reactivity only in 20W and 32W respectively. Though ConA reacted in all fetal period, significant changes occurred during 28W. It showed negative reactivity in luminal cells, strong positive reactivity in intermediate cells and weak reactivity in basal cells. ConA showed extensive, moderate and weak reaction in luminal, intermediate and basal cells individually during 8W, 14W, 20W and 32W. No reactivity could be observed in PNA, LCA and SBA. These results indicate that a variety of lectin binding sites are present in the development of fetal esophageal epithelium. Alterations in cell surface or pericellular matrix carbohydrates may affect cell to cell matrix interactions and modify responses of target cells to effector molecules that may be essential for the support of fetal esophageal epithelium development.