Department of Veterinary Clinical Sciences, the Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, UK.
Theriogenology. 2012 Apr 1;77(6):1100-10. doi: 10.1016/j.theriogenology.2011.10.012. Epub 2012 Jan 5.
The natural cervical relaxation which occurs at estrus in the ewe may be initiated by binding of hyaluronan (HA) to its receptor CD44. Indeed, we have previously shown that HA content and fragment size in the ovine cervix varies with the stage of the estrous cycle. Despite the importance of cervical relaxation in promoting sperm transport and facilitating the possible development of transcervical artificial insemination (AI), the mechanisms coordinating these changes in HA content remain to be defined. Hyaluronan synthases (HAS) 1, 2, and 3 regulate HA biosynthesis and herein, we describe the changing pattern of HAS isoform expression during the estrous cycle to determine whether this may underpin HA-mediated changes in relaxation of the ovine cervix. Accordingly, cervices were collected from 24 cyclic sheep (n = 8 / group) at the luteal, pre-luteinizing hormone (LH) and post-LH surge stages. Protein and mRNA expression for HAS 1, 2 and 3 was determined in five different tissue layers (epithelium, subepithelial stroma, and longitudinal, circular and transverse muscle) of the vaginal, mid and uterine regions of each cervix by immunohistochemistry and in situ hybridization, respectively. HA synthases were expressed in all the tissue layers and regions of the cervix, and the pattern of expression was similar for mRNA and protein. HAS1 protein and mRNA expression was significantly (P ≤ 0.05) higher at the pre-LH surge stage, while HAS 2 and 3 protein and mRNA expression was significantly (P ≤ 0.001) higher at the luteal stage. Overall, both HAS protein and mRNA expression was significantly (P ≤ 0.001) higher in the epithelial layer and the vaginal region. These findings are in accordance with our previous results and explain the differences observed in the HA content and differing HA fragment size at different stages of the estrous cycle.
发情期母羊的自然宫颈松弛可能是由透明质酸（HA）与其受体 CD44 结合引发的。事实上，我们之前已经表明，绵羊宫颈中的 HA 含量和片段大小随发情周期的阶段而变化。尽管宫颈松弛对于促进精子运输和促进经宫颈人工授精（AI）的发展非常重要，但协调这些 HA 含量变化的机制仍有待确定。透明质酸合酶（HAS）1、2 和 3 调节 HA 的生物合成，在此，我们描述了发情周期中 HAS 同工型表达的变化模式，以确定这是否可以为 HA 介导的绵羊宫颈松弛变化提供基础。因此，从 24 只发情周期的绵羊（n = 8 / 组）中采集发情周期的黄体、促黄体激素（LH）前和 LH 峰后阶段的宫颈。通过免疫组织化学和原位杂交，分别在阴道、中部和子宫区域的每个宫颈的五个不同组织层（上皮、上皮下基质以及纵向、环形和横向肌肉）中确定 HAS1、2 和 3 的蛋白和 mRNA 表达。HA 合酶在宫颈的所有组织层和区域中表达，mRNA 和蛋白的表达模式相似。HAS1 蛋白和 mRNA 表达在 LH 前峰期显着（P ≤ 0.05）升高，而 HAS 2 和 3 蛋白和 mRNA 表达在黄体期显着（P ≤ 0.001）升高。总体而言，上皮层和阴道区域的 HAS 蛋白和 mRNA 表达均显着（P ≤ 0.001）更高。这些发现与我们之前的结果一致，并解释了发情周期不同阶段观察到的 HA 含量和不同 HA 片段大小的差异。
