Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
Reproduction. 2011 Dec;142(6):879-92. doi: 10.1530/REP-11-0157. Epub 2011 Sep 20.
The corpus luteum (CL), which secretes large amounts of progesterone and is thus essential for establishing pregnancy, contains various types of immune cells that may play essential roles in CL function by generating immune responses. The lymphatic system is the second circulation system and is necessary for immune function, but the lymphatic system of the bovine CL has not been characterized in detail. We collected bovine CLs on days 12 and 16 of the estrous cycle (C12 and C16) and days 16 and 40 of early pregnancy (P16 and P40). Lymphatic endothelial hyaluronan receptor 1 (LYVE1) protein was detected in the CL by immunohistochemistry and western blotting and increased at P40 compared with C16. The mRNA expression levels of lymphangiogenic factors, such as vascular endothelial growth factor-C (VEGFC), VEGFD, and their common receptor VEGFR3, as well as the lymphatic endothelial cell (LyEC) marker podoplanin, increased in P16 and P40 CLs. Thus, it is suggested that the lymphatic system of the bovine CL reconstitutes during early pregnancy. Interferon tau (IFNT) from the conceptus in the uterus is a candidate for activating luteal lymphangiogenesis during the maternal recognition period (MRP). We found that treatment of LyECs isolated from internal iliac lymphatic vessels with IFNT stimulated LyEC proliferation and significantly increased mRNA expression of VEGFC and IFN-stimulated gene 15. Moreover, both IFNT and VEGFC induced LyECs to form capillary-like tubes in vitro. In conclusion, it is suggested that new lymphangiogenesis in the bovine CL begins during the MRP and that IFNT may mediate this novel phenomenon.
黄体（CL）大量分泌孕激素，对于妊娠的建立至关重要，其中包含多种类型的免疫细胞，这些细胞可能通过产生免疫反应，在 CL 功能中发挥重要作用。淋巴系统是第二循环系统，对于免疫功能至关重要，但牛 CL 的淋巴系统尚未得到详细描述。我们在发情周期的第 12 天和第 16 天（C12 和 C16）以及妊娠早期的第 16 天和第 40 天（P16 和 P40）收集牛 CL。通过免疫组织化学和 Western blot 检测到 CL 中的淋巴管内皮透明质酸受体 1（LYVE1）蛋白，其在 P40 时较 C16 增加。血管内皮生长因子-C（VEGFC）、VEGFD 及其共同受体 VEGFR3 等淋巴管生成因子以及淋巴管内皮细胞（LyEC）标志物 podoplanin 的 mRNA 表达水平在 P16 和 P40 CL 中增加。因此，提示牛 CL 的淋巴系统在妊娠早期重建。子宫内的合胞体滋养层细胞产生的干扰素 tau（IFNT）可能是母体识别期（MRP）中黄体淋巴管生成的激活因子。我们发现，用 IFNT 处理从髂内淋巴管分离的 LyEC，刺激 LyEC 增殖，并显著增加 VEGFC 和 IFN 刺激基因 15 的 mRNA 表达。此外，IFNT 和 VEGFC 均可诱导 LyEC 体外形成毛细血管样管。总之，提示牛 CL 中的新淋巴管生成始于 MRP，IFNT 可能介导这一新现象。
