Mohamedien Dalia, Gaber Wafaa, Hirayama Makoto, Awad Mahmoud
Department of Histology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt,
Amphibian Research Center, Hiroshima University, Hiroshima, Japan,
Cells Tissues Organs. 2025;214(4):245-257. doi: 10.1159/000541836. Epub 2024 Oct 11.
Mucins are polydisperse molecules created to perform a variety of functions at the mucosal surface of the adult gastrointestinal tract. Two main groups of mucins could be identified: the membrane-associated mucins (MUC1, MUC4, MUC13, and MUC16), those bound to the apical plasma membrane of epithelial cells, and the secreted mucins (MUC2, MUC5AC, MUC5B, and MUC6), those secreted from the goblet cells. Little is known about the types and distribution patterns of mucins in prenatal life.
We detected mucin-secreting cells in the developing rabbit esophagus though these cells are absent in the adult one. In order to identify the content and possible functions of these cells, we investigated the histochemical and immunohistochemical characteristics of their mucins.
Starting at 16th day of pregnancy, periodic acid Schiff (PAS), alcian blue (AB) pH (2.5), and PAS-AB combination intensely stained the mucous content, demonstrating both acidic and neutral mucopolysaccharides. Some blebs could be recognized on the free surface of the esophageal epithelium. Also, the mucous cells and some basal cells strongly immunoreacted with MUC1, but not MUC2, nor MUC5AC antibodies.
Collectively, these data suggest that surface mucous cells are modified epithelial cells, not goblet cells, and may originate from the basal layer of the epithelial cells. A possible regulatory role for these MUC1-positive mucins in esophageal epithelial and mesenchymal cell differentiation and late organogenesis is suggested. However, future functional studies are recommended.
黏蛋白是多分散分子，在成人胃肠道黏膜表面发挥多种功能。可识别出两大类黏蛋白：膜相关黏蛋白（MUC1、MUC4、MUC13和MUC16），它们与上皮细胞的顶端质膜结合；分泌型黏蛋白（MUC2、MUC5AC、MUC5B和MUC6），它们由杯状细胞分泌。关于产前生活中黏蛋白的类型和分布模式知之甚少。
我们在发育中的兔食管中检测到了黏蛋白分泌细胞，而成年兔食管中不存在这些细胞。为了确定这些细胞的内容物和可能的功能，我们研究了其黏蛋白的组织化学和免疫组织化学特征。
从妊娠第16天开始，过碘酸希夫（PAS）、阿尔辛蓝（AB）pH（2.5）以及PAS-AB联合染色强烈显示了黏液成分中的酸性和中性黏多糖。在食管上皮的游离表面可识别出一些小泡。此外，黏液细胞和一些基底细胞与MUC1抗体发生强烈免疫反应，但与MUC2和MUC5AC抗体无反应。
总体而言，这些数据表明表面黏液细胞是经过修饰的上皮细胞，而非杯状细胞，可能起源于上皮细胞的基底层。提示这些MUC1阳性黏蛋白在食管上皮和间充质细胞分化以及晚期器官形成中可能具有调节作用。然而，建议未来进行功能研究。
