Transcriptomic analysis of luteal tissue supports the earlier onset of luteolysis in heifers with diminished ovarian reserve

Martim Kaps; Alexandria Snider; Lacey Quail; Jeremy Miles; George Perry; Robert Cushman

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Transcriptomic analysis of luteal tissue supports the earlier onset of luteolysis in heifers with diminished ovarian reserve

Martim Kaps, Alexandria Snider, Lacey Quail, Jeremy Miles , George Perry , Robert Cushman

Abstract

Context. Antral follicle count (AFC) is reflective of ovarian reserve and linked to reproductive performance in mammalian females. We previously demonstrated earlier upregulation of endometrial oxytocin receptor transcription in heifers with low AFC, indicating an earlier onset of luteolysis. Aims. We aimed to support the earlier onset of luteolysis in Open Low AFC heifers and hypothesized a reduced abundance of luteinizing hormone/choriogonadotropin receptor (LH/CG-R) and increased thrombospondin-1 (THBS1) abundance in luteal tissue of those heifers. We further investigated if classical interferon stimulated genes (ISGs) are already upregulated in response to conceptus-derived interferon tau. Methods. For four years, ten heifers with the highest (High AFC) and ten heifers with the lowest (Low AFC) of the population (n = 120/year) were selected, synchronized and inseminated. On day 15 or 16 after insemination, reproductive tracts were collected, and pregnancy status was determined. Corpora lutea were isolated, weighed and underwent transcriptomic analysis. Key results. Transcript abundance of LH/CG-R was lower in Open Low AFC heifers compared to all other subgroups. Transcript abundance of THBS1 was upregulated in Open vs. Pregnant heifers and showed greater abundance in Low vs. High AFC heifers. Luteal weights and abundance of ISGs did not differ between heifers of differing AFC Groups or Pregnancy Status. Conclusions. The patterns of luteal LH/CG-R and THBS1 abundance support the concept of earlier onset of luteolysis in Open heifers with diminished AFC. Implications. This may result in a shorter window for maternal recognition of pregnancy and contribute to inferior reproductive performance.

RD24130 Accepted 31 October 2024