Local effect of the conceptus on uterine vascular perfusion during early pregnancy in heifers

Abstract

Colour-Doppler ultrasonography was used to study the spatial relationship between vascular perfusion in the middle of each uterine horn and the reported location of the embryo proper and expanding conceptus using endometrial vascularity scores 1-4 (nil-maximal). Vascularity increased in both uterine horns between days 14 and 18 (day 0Zovulation) in nonpregnant heifers (nZ6) but not in pregnant heifers (nZ11). The increase was temporally associated with decreasing plasma progesterone and increasing oestradiol. In pregnant heifers, a transient increase in endometrial vascularity in the ipsilateral horn (horn with embryo) was not detected before day 18, despite a reported transient increase in blood flow in the ipsilateral uterine artery between days 13 and 17. Endometrial vascularity in the ipsilateral horn first increased (P!0.05) between days 18 and 20. Day 20 is the reported day of adhesiveness between chorion and uterus. An increase (P!0.05) in the contralateral horn between days 18 and 22 was slight, but a greater increase occurred after day 32. Day 32 is the reported day of entry of the allantochorion into the contralateral horn. By day 42, scores were similar between the two horns, and the allantochorion reportedly fills both horns. On days 42-60, at a time when placentomes apparently are limited to the ipsilateral horn, vascularity remained elevated in the ipsilateral horn but decreased in the contralateral horn. Results support the hypothesis that vascular perfusion in each uterine horn during early pregnancy is mediated by direct contact between conceptus and uterus.

Increase of essential amino acids in the bovine uterine lumen during preimplantation development

“…For SLC1A5 and SLC6A6 transcripts, we observed an increase over time, possibly induced by progesterone exposure as previously demonstrated in the ewe for SLC1A5 (Gao et al 2009b). Blood flow increases from days 14 to 18 in the uterine artery supplying the gravid uterine horn with sufficient nutrients (Ford et al 1979, Silva & Ginther 2010. This may enable an accumulation of nutrients even in the absence of increases in expression of genes for most solute carriers.…”

Follicle and corpus luteum size and vascularity as predictors of fertility at the time of artificial insemination and embryo transfer in beef cattle

“…Color-Doppler ultrasonography was previously used in cows to evaluate the vascularity of follicle, CL, and conceptus (Myamoto et al 2005, Pareja et al 2010, Silva et al 2010). Therefore, since it is a non invasive technique and with reliable application, it is a useful tool to target new reproductive diagnoses.…”

Conceptus-mediated endometrial vascular changes during early pregnancy in mares: an anatomic, histomorphometric, and vascular endothelial growth factor receptor system immunolocalization and gene expression study

“…In this fixed position, the conceptus continues its spherical growth but spreads rostrally and caudally due to relatively low resistance at these areas of the uterus. Studies using Doppler ultrasonography have described significant uterine and embryonic vascular changes at this time in mares (Silva et al 2005 as well as cows (Silva & Ginther 2010). Pertinent to this study, an increase in endometrial blood flow is associated with conceptus presence during the mobility phase of early pregnancy in mares (Silva et al 2005.…”