In vivo modulation of the immune system by conceptus signaling between days 15 and 20 of gestation in cattle

• Grant number: 24/16341-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2024
• End date: September 30, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Guilherme Pugliesi
• Grantee: Ana Karolyne Alves Miguel
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 22/14936-7 - Innate immune response to conceptus signaling in early pregnancy in cattle, AP.R

Abstract

The main goal with the present study is to understand the maternal response to conceptus signaling between days 15 to 20 of gestation, in order to comprehend the modulation of immune system associated with early embryonic loss and to identify, at an early stage, the gestational status in bovine females. For this purpose, Nelore heifers (n=40) will undergo an estrus synchronization protocol and subsequent embryo transfer (ET) procedure. The day on which estrus is observed will be considered day 0 (D0). After seven days (D7), the animals will be divided into the TE group (n=30) and the SHAM group (n=10). Peripheral blood samples will be collected to measure plasma progesterone (P4) concentrations, and color-Doppler ultrasound examinations of the CL will be performed on days 7, 15 and 20 after estrus. The animals will be slaughtered on days 15 and 20 (ET group = 15/day; SHAM group = 5/day). After slaughter, the uterine horns will be washed to recover the conceptus and an endometrial biopsy will be performed for later analysis. The endometrial tissue and uterine flushing will be frozen for gene expression analysis by RT-PCR and determination of cytokine concentration by Multiplex System. Furthermore, the IFN-t concentration in the uterine flushing will be determined by ELISA. We anticipate that the understanding of the local and circulating maternal response to concept us during early pregnancy using this proposed in vivo model will potentially result in discovery of novel pregnancy markers that could be determined in peripheral blood or immune cells. Therefore, our main objective with the present study is to understand the maternal response to conceptus signaling between days 15 and 20 of gestation, in order to understand the modulation of the immune system associated with early embryonic loss and to identify, at an early stage, the gestational state in bovine females.