Argüeso Pablo, Spurr-Michaud Sandra, Tisdale Ann, Gipson Ilene K
Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.
J Clin Endocrinol Metab. 2002 Dec;87(12):5641-8. doi: 10.1210/jc.2002-020766.
It has been hypothesized that the carbohydrate portion of mucins present in the endocervical canal plays an important role in conferring specific physicochemical properties (e.g. viscosity and hydration) to the mucus gel through the menstrual cycle. Our recent finding showing an increase in the amount of MUC5B mucin protein at midcycle has raised the question of whether the mucin O-glycan content also varies to confer specific hydrodynamic properties to secreted mucins during ovulation. Using lectins as carbohydrate probes, we have identified two common mucin oligosaccharide structures, T antigen and N-acetyllactosamine, within secretory granules in human endocervical glands during the proliferative phase of the menstrual cycle. Analysis of endocervical secretions by enzyme-linked lectin assay revealed that the amounts of T antigen and N-acetyllactosamine are maximal at midcycle. Lectin blot assay of immunoprecipitated MUC5B demonstrated that the mucin is a carrier of the T antigen and N-acetyllactosamine oligosaccharides in cervical mucus secretions. The amounts of T antigen and N-acetyllactosamine oligosaccharides on MUC5B increased during the first half of the cycle, peaked at midcycle, and dramatically dropped at the end of the cycle. The peak in MUC5B mucin protein and carbohydrate content coincides with the change in mucus character that occurs at midcycle. The role of O-glycans on mucins may be to hold water within the endocervical canal during ovulation to facilitate sperm migration.
有假说认为，宫颈管中存在的黏蛋白的碳水化合物部分在整个月经周期中赋予黏液凝胶特定的物理化学性质（如粘度和水合作用）方面发挥着重要作用。我们最近的研究发现，在月经周期中期MUC5B黏蛋白的含量增加，这就提出了一个问题，即黏蛋白O-聚糖含量在排卵期间是否也会发生变化，从而赋予分泌的黏蛋白特定的流体动力学性质。我们使用凝集素作为碳水化合物探针，在月经周期增殖期的人宫颈腺分泌颗粒中鉴定出两种常见的黏蛋白寡糖结构，T抗原和N-乙酰乳糖胺。通过酶联凝集素测定法分析宫颈分泌物发现，T抗原和N-乙酰乳糖胺的含量在月经周期中期达到最大值。对免疫沉淀的MUC5B进行凝集素印迹分析表明，该黏蛋白是宫颈黏液分泌物中T抗原和N-乙酰乳糖胺寡糖的载体。MUC5B上的T抗原和N-乙酰乳糖胺寡糖的含量在月经周期的前半期增加，在月经周期中期达到峰值，并在月经周期结束时急剧下降。MUC5B黏蛋白和碳水化合物含量的峰值与月经周期中期发生的黏液特性变化相吻合。黏蛋白上O-聚糖的作用可能是在排卵期间将水分保留在宫颈管内，以便于精子迁移。
