目的　研究人胚胎气管上皮细胞分化过程中 ,粘蛋白 MU C1、MUC2和 MUC5 ac的表达 ,以及MU C5 ac m RNA的表达。　方法　免疫组织化学及原位杂交技术。　结果　胚胎气管上皮细胞中 MU C1呈阴性表达 ,不同胎龄的胚胎气管上皮细胞 MUC2和 MU C5 ac均呈阳性表达。胚胎气管上皮的细胞核及胞浆中 MUC5 acm RNA呈阳性表达。　结论　胚胎气管上皮均能产生 MU C2和 MUC5 ac粘蛋白 ,而且 MUC5 ac蛋白表达是在转录水平进行的 Objective To investigate the expression of mucins MU C1, MUC2 and MUC5 ac and the expression of MU C5 ac m RNA during the differentiation of human embryonic tracheal epithelial cells. Methods Immunohistochemistry and in situ hybridization. Results MU C1 was negatively expressed in embryonic tracheal epithelial cells, and both MUC2 and MU C5 ac of embryonic tracheal epithelial cells of different gestational ages were positive. MUC5 acm RNA was positive in nucleus and cytoplasm of embryonic tracheal epithelium. Conclusions Both MU C2 and MUC5 ac mucin can be produced in embryonic tracheal epithelium, and MUC5 ac protein expression is at transcriptional level