How immune-related and interferon-stimulated genes are temporally regulated in cytologic uterine samples of embryo recipients with pregnancy success or loss?

• Ano de defesa: 2025
• Autor(a) principal: Souza, Samuel Volpe
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Beef cow; Cytobrush; Endométrio; Endometrium; Gestação; Immune response; Pregnancy; Resposta Imune; Vaca de corte
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/10/10131/tde-14082025-164359/

This study aimed to determine the endometrial response to conceptus signaling during early pregnancy in heifers submitted to embryo transfer (ET). Nelore heifers were subjected to an estrous cycle synchronization protocol and monitored daily to determine the time of ovulation (Day 1) using transrectal ultrasonography. The animals were randomly divided into two procedures, SHAM (n=15) and ET (n=71). SHAM or TE procedures were performed on the uterine horn ipsilateral to the CL on Day 7. Surface cells from the endometrium were collected using a cytobrush for gene expression analysis (qPCR) followed by a Doppler ultrasound (Doppler-US) to measure the area and blood perfusion of the corpus luteum (CL) on Days 6, 15, and 20. After collecting the samples, the animals were divided into five groups for analysis: The cycling group (n=8) compound by cycling heifers that only received the simulated ET procedure (SHAM); EL15- 20 group (n=8) heifers that received ET, with luteolysis detected on Day 20; EL20-25 group (n=8) heifers that received ET, but with luteolysis detected on Day 25; EL25-30 group (n=8), heifers that received ET, but without the presence of a viable embryo on Day 30 and Pregnant group (n=6), heifers that received ET and had their pregnancy confirmed with the presence of an embryo and a heartbeat on Day 30. Interferon-stimulated genes (ISG15, RSAD2 and IRF2) and immune response-related genes (IL1β, IL8, TNFα, IFNγ, IL6, IL10, TGFβ1, TLR2 and TLR4) were analyzed. The data were analyzed by ANOVA, using the PROC MIXED procedure of SAS. There was an increase in the expression of ISG15 and RSAD2 for the EL20-25, EL25-30, and Pregnant groups on Day 15, which was maintained until Day 20. For IRF2, expression was decreased on Day 15 in heifers from the Pregnant group. Heifers in the Pregnant group also showed an increase in the expression of the cytokines IFNγ (pro-inflammatory), IL6 and IL10 (anti-inflammatory) on Day 20. However, the expression of the inflammatory cytokines IL1β and IL8 increased on Day 20 in heifers in the EL20-25 and EL25-30 groups. For the Cycling and EL-15-20 groups, an increase in TGFβ1 was observed on Day 20. For TLR2, an increase in its expression was observed between Days 6 and 20 for heifers in the EL-20-25, EL25-30, and Pregnant groups; while its expression increased between Days 6 and 15 and then decreased between Days 15 and 20 in the Cycling and EL15-20 groups. The expression of TLR4 increased in all groups, except in the Pregnant group. It is concluded that the presence of the embryo stimulates the expression of ISG15, RSAD2, IL6, IL10, IFNγ, and TLR2 in embryo recipients that maintained active CL until Day 20, regardless of the success in establishing pregnancy. On the other side, the modulation of IL1β, IL8, and TLR4 expression is associated with the success of embryo maintenance and pregnancy establishment.