Sharjah Equine Hospital, Al Daid Road, Bridge No.6, Al Atain Area, Sharjah, United Arab Emirates; The Paul Mellon Laboratory of Equine Reproduction, "Brunswick", Newmarket, Suffolk, CB8 9BJ, UK.
Newcombe and East Veterinary Surgeons, Brownhills, West Midlands, WS8 6LS, UK.
Placenta. 2019 Sep 15;85:32-39. doi: 10.1016/j.placenta.2019.08.081. Epub 2019 Aug 8.
The proteins galectin-1 and Progesterone Induced Blocking Factor (PIBF) are present on human and murine trophoblast and are thought to influence both immunomodulation and trophoblast invasion. In equids, the invasive component of the placenta, the endometrial cups, stimulate maternal cell-mediated and humoral immune responses. It was therefore of interest to know if galectin-1 or PIBF could be immunolocalised to the invasive and/or non-invasive components of the equine placenta.
Horse and mule (♀ horse X ♂ donkey) embryos and placental tissues between Days 12 and 124 of gestation were stained immunohistochemically with antibodies raised against galectin-1 and PIBF.
Galectin-1 stained the non-invasive trophoblast between Days 15 and 20 but thereafter stained only the invasive trophoblast cells of the chorionic girdle, both before and after they invaded the endometrium to form the endometrial cups. PIBF, on the other hand, stained both the invasive and non-invasive trophoblast throughout the period of gestation studied. Of particular interest was the relative lack of staining of the endometrial cup cells in mule compared to horse pregnancies for galectin-1 and PIBF prior to the earlier and more rapid death and desquamation of the mule cup cells.
The expression of galectin-1 and PIBF proteins in equine trophoblast and the marked difference in lifespan between the endometrial cups in intraspecies horse versus interspecies mule pregnancies support a likely role for these two proteins protecting the fetal trophoblast from maternal immune attack and/or modulation of the invasiveness of endometrial cup cells.
半乳糖凝集素-1 和孕激素诱导阻断因子（PIBF）存在于人和鼠的滋养层细胞中，被认为会影响免疫调节和滋养层细胞的侵袭。在马属动物中，胎盘的侵袭部分，即子宫内膜杯，会刺激母体细胞介导和体液免疫反应。因此，人们有兴趣了解半乳糖凝集素-1 或 PIBF 是否可以免疫定位到马属动物胎盘的侵袭和/或非侵袭部分。
马和骡子（♀马 X ♂驴）胚胎和妊娠 12 至 124 天的胎盘组织，用针对半乳糖凝集素-1 和 PIBF 的抗体进行免疫组织化学染色。
半乳糖凝集素-1 在妊娠第 15 至 20 天染色非侵袭性滋养层，但此后仅染色绒毛膜带的侵袭性滋养层细胞，在它们侵入子宫内膜形成子宫内膜杯之前和之后都是如此。另一方面，PIBF 在整个妊娠期间均染色侵袭性和非侵袭性滋养层。特别有趣的是，在马和骡子的妊娠中，与马相比，骡子的子宫内膜杯细胞在半乳糖凝集素-1 和 PIBF 染色方面相对缺乏，这与骡子杯细胞更早和更快的死亡和脱落有关。
半乳糖凝集素-1 和 PIBF 蛋白在马属动物滋养层中的表达，以及同种马与异种骡子妊娠中子宫内膜杯寿命的显著差异，支持这两种蛋白可能起到保护胎儿滋养层免受母体免疫攻击和/或调节子宫内膜杯细胞侵袭性的作用。
