Instituto Superior de Investigaciones Biológicas CONICET, Química y Farmacia Universidad Nacional de Tucumán, Tucumán, Argentina.
Anim Reprod Sci. 2010 Apr;118(2-4):344-53. doi: 10.1016/j.anireprosci.2009.07.008. Epub 2009 Jul 28.
Sperm binding to oviductal epithelium would be involved in sperm reservoir formation in the utero tubal junction (UTJ). Although in other mammals sperm-oviduct interaction has been proved to be mediated by carbohydrate-recognition mechanisms, the factors implicated in the sperm adhesion to oviductal epithelium of llama are still unknown. In order to assess the role of carbohydrates present in the mucosa surface, we examined the distribution of glycoconjugates in the llama oviduct by confocal lectin-histochemistry. Mannosyl, glucosyl, N-acetylglucosaminyl, galactosyl, N-acetylgalactosaminyl and sialic acid residues were detected in the oviductal mucose glycocalyx. By incubation of UTJ oviductal explants with LCA, DBA, UEA-1 or PNA lectin previous to co-culture with sperm, we observed a significant decrease in sperm binding only with LCA lectin. In the mucosa surface there were numerous d-glucosyl and D-manosyl residues, which were spotted by this lectin. Probably, this fact promotes the whole covering of the oviduct luminal surface by the sugar-lectin complex, preventing sperm access and adhesion of further residues. However, sperm incubation with mannose or glucose does not significantly prevent binding, which means that glucose and mannose would not be involved in a specific sperm-oviduct interaction. On the other hand, we observed a high reduction in sperm binding to UTJ explants with N-acetylgalactosamine and galactose (p<0.001). Coincidentally, binding sites for N-acetylgalactosamine-PAA-FITC conjugate were observed on the whole surface of the sperm, supporting the concept that llama sperm have lectin-like molecules in their surface, as is the case in other mammals. Probably, these lectin-like molecules, by means of N-acetylgalactosamine and galactose recognition, could link the sperm to the oviductal mucosa with the purpose of forming storing sites in the UTJ. Our results support the idea that more than one carbohydrate could participate in sperm reservoir formation in the llama UTJ oviductal segment.
精子与输卵管上皮的结合将参与到子宫输卵管交界处（UTJ）的精子库形成中。虽然在其他哺乳动物中，已经证明精子-输卵管相互作用是通过碳水化合物识别机制介导的，但 llama 输卵管上皮中涉及精子黏附的因素仍不清楚。为了评估黏膜表面存在的碳水化合物的作用，我们通过共聚焦凝集素组织化学检查了 llama 输卵管中的糖缀合物分布。在输卵管黏膜糖萼中检测到甘露糖基、葡萄糖基、N-乙酰葡萄糖胺基、半乳糖基、N-乙酰半乳糖胺基和唾液酸残基。通过在用 LCA、DBA、UEA-1 或 PNA 凝集素孵育 UTJ 输卵管外植体之前，与精子共培养，我们仅观察到与 LCA 凝集素孵育后精子结合显著减少。在黏膜表面有许多 d-葡萄糖基和 D-甘露糖基残基，这些残基被该凝集素标记。可能正是这种情况促进了糖-凝集素复合物对输卵管腔表面的全面覆盖，从而阻止了精子的进入和进一步残基的黏附。然而，精子与甘露糖或葡萄糖孵育并不能显著阻止结合，这意味着葡萄糖和甘露糖不会参与特定的精子-输卵管相互作用。另一方面，我们观察到与 N-乙酰半乳糖胺和半乳糖孵育的 UTJ 外植体的精子结合显著减少（p<0.001）。巧合的是，在精子的整个表面都观察到了与 N-乙酰半乳糖胺-PAA-FITC 缀合物的结合位点，这支持了 llama 精子表面存在类似凝集素的分子的概念，就像在其他哺乳动物中一样。可能这些类似凝集素的分子通过 N-乙酰半乳糖胺和半乳糖的识别，将精子与输卵管黏膜连接起来，目的是在 UTJ 中形成储存部位。我们的结果支持这样一种观点，即在 llama UTJ 输卵管段的精子库形成中，可能有不止一种碳水化合物参与。
