抄録
[Introduction] Day 7 (D7) embryos communicate with the bovine uterus for embryo recognition mainly via embryo-derived interferon tau (IFNT). However, the definite impact of INFT on the composition of the uterine luminal fluid (ULF) is not completely understood. We aimed to investigate effects of in vivo intrauterine infusion of recombinant bovine INFT (rbINFT) on protein contents of ULF at D8 post-estrus in cows. [Materials and methods] Five Holstein cows were estrus synchronized and received a non-surgical intrauterine infusion of 100 ml Ringer solution on D6 post-estrus, collected 24 h later, and kept as a control-1. The same procedure was repeated on D7 and kept as a control-2. On D8, 100 ml Ringer solution containing rbIFNT (100 pg/ml) were infused, collected 24 h later, and kept as a treatment. The collected ULF was exposed to 2D gel electrophoresis and mass spectrometry (MS) analysis. Bovine endometrial epithelial cells (BEECs) were stimulated by rbIFNT (10 ng/ml) for 24 h and culture supernatants were exposed to the same proteome analysis. [Results] Differential proteomic analysis of ULF showed higher protein contents in IFNT-treated cows compared to controls. MS analysis identified the upregulation of Apolipoprotein-A1 (Apo-A1) of the truncated spot from the electrophoresis Gel in IFNT-treated cows compared to controls. Additionally, the infusion of INFT increased Apo-A1 protein levels in ULF as detected by ELISA. Similar results were obtained with BEECs stimulated by rbIFNT (10 ng/ml). Stimulation of peripheral blood mononuclear cells by recombinant bovine Apo-A1 upregulated mRNA expressions of anti-inflammatory cytokines (TGFB1) and downregulated pro-inflammatory cytokines (TNFA, and IL1B) in vitro. Our findings provide the in vivo evidence that a physiological level of embryo-derived INFT (100 pg/ml) stimulates endometrial epithelium to release Apo-A1 which induces anti-inflammatory responses in immune cells for embryo tolerance and pregnancy establishment in cows.
