Gram Aykut, Redmer Dale A, Kowalewski Mariusz P, Dorsam Sheri T, Valkov Veselina, Warang Prajakta, Reyaz Arshi, Bass Casie S, Kaminski Samantha L, Grazul-Bilska Anna T
Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Department of Animal Sciences, North Dakota State University, Fargo, ND 58108, USA.
Gen Comp Endocrinol. 2018 Dec 1;269:131-140. doi: 10.1016/j.ygcen.2018.09.003. Epub 2018 Sep 5.
The aim of this study was to evaluate angiopoietin (ANGPT) 1 and 2, and tyrosine-protein kinase receptor 2 (TIE2) expression in the corpora lutea (CL) of FSH-treated, or non-treated sheep administered arginine (Arg) or vehicle (saline, Sal), and fed a control (C), excess (O) or restricted (U) diet. Ewes from each dietary group were treated with Arg or Sal (experiment 1), and with FSH (experiment 2). Luteal tissues were collected at the early-, mid- and/or late-luteal phases of the estrous cycle. Protein and mRNA expression was determined using immunohistochemistry followed by image analysis, and quantitative RT-PCR, respectively. The results demonstrated that ANGPT1 and TIE2 proteins were localized to luteal capillaries and endothelial cells of larger blood vessels, and ANGPT2 was localized to tunica media of larger blood vessels. TIE2 protein was also present in luteal cells. In experiment 1, ANGPT1 protein expression was greater in O than C during early- and mid-luteal phases, and was greatest during late-luteal phase, less at the mid- and least at the early-luteal phase; 2) TIE2 protein expression was greatest at the mid-, less at the early- and least at the late-luteal phase; 3) ANGPT1 and 2 mRNA expression was greater at the mid- and late- than the early-luteal phase, and TIE2 mRNA expression was greatest at the late-, less at the mid- and least at the early-luteal phase. The ANGPT1/2 ratio was less at the early- than mid- or late-luteal phases. In experiment 2, ANGPT1 protein expression was greater in O during the mid-luteal phase than in other groups, and was greater at the mid- than early-luteal phase. TIE2 protein expression was highest at the mid-, less at the early- and least during the late-luteal phase. ANGPT1 and 2, and TIE2 mRNA expression was higher at the mid- than the early-luteal phase. During mid-luteal phase, ANGPT1 mRNA expression was greater in C than O and U, ANGPT2 was greatest in C, less in O and least in U, and TIE2 mRNA expression was greater in C than O and U. The ANGPT1/2 ratio was higher in U than in any other group. Comparison of FSH vs. Sal treatment effects (experiment 2 vs. experiment 1) demonstrated that FSH affected ANGPT1 and/or -2, and TIE2 protein and mRNA expression depending on luteal phase and/or diet. Thus, expression of ANGPTs and TIE2 in the CL changes during the luteal lifespan, indicating their involvement in luteal vascular formation, stabilization and degradation. Moreover, this study has demonstrated that plane of nutrition and/or FSH treatment affect the ANGPT system, and may alter luteal vascularity and luteal function in sheep.
本研究旨在评估血管生成素（ANGPT）1和2以及酪氨酸蛋白激酶受体2（TIE2）在经促卵泡素（FSH）处理或未处理的绵羊黄体（CL）中的表达情况，这些绵羊分别给予精氨酸（Arg）或赋形剂（生理盐水，Sal），并饲喂对照（C）、过量（O）或受限（U）日粮。每个日粮组的母羊分别接受Arg或Sal处理（实验1）以及FSH处理（实验2）。在发情周期的黄体早期、中期和/或晚期收集黄体组织。分别采用免疫组织化学结合图像分析和定量逆转录聚合酶链反应（qRT-PCR）测定蛋白质和mRNA表达。结果表明，ANGPT1和TIE2蛋白定位于黄体毛细血管和较大血管的内皮细胞，ANGPT2定位于较大血管的中膜。TIE2蛋白也存在于黄体细胞中。在实验1中，ANGPT1蛋白表达在黄体早期和中期O组高于C组，在黄体晚期最高，中期较少，早期最少；2）TIE2蛋白表达在黄体中期最高，早期较少，晚期最少；3）ANGPT1和2的mRNA表达在黄体中期和晚期高于早期，TIE2的mRNA表达在黄体晚期最高，中期较少，早期最少。ANGPT1/2比值在黄体早期低于中期和晚期。在实验2中，ANGPT1蛋白表达在黄体中期O组高于其他组，且中期高于早期。TIE2蛋白表达在黄体中期最高，早期较少，晚期最少。ANGPT1和2以及TIE2的mRNA表达在黄体中期高于早期。在黄体中期，ANGPT1的mRNA表达在C组高于O组和U组，ANGPT2在C组最高，O组较少，U组最少，TIE2的mRNA表达在C组高于O组和U组。ANGPT1/2比值在U组高于其他任何组。比较FSH与Sal处理的效果（实验2与实验1）表明，FSH对ANGPT1和/或 -2以及TIE2蛋白和mRNA表达的影响取决于黄体期和/或日粮。因此，ANGPTs和TIE2在黄体期的表达在黄体寿命期间发生变化，表明它们参与黄体血管形成、稳定和退化。此外，本研究表明营养水平和/或FSH处理会影响ANGPT系统，并可能改变绵羊的黄体血管生成和黄体功能。
