Analysis of microRNA expression between gestational ages in Nellore cattle

• Ano de defesa: 2024
• Autor(a) principal: Assis, Thaís Rodrigues Monteiro de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Zootecnia
• Palavras-chave em Português: Nelore (Bovino) - Reprodução; MicroRNAs; Nelore (Bovino) - Gestação; Marcadores genéticos; Plasma; CIENCIAS AGRARIAS::ZOOTECNIA::GENETICA E MELHORAMENTO DOS ANIMAIS DOMESTICOS
• Link de acesso: https://locus.ufv.br/handle/123456789/33294; https://doi.org/10.47328/ufvbbt.2024.772

Most pregnancy losses in high-yielding cows occur within the first three weeks after insemination. To better monitor embryonic development, some studies have identified numerous miRNAs expressed in the placenta, highlighting them as potential markers for tracking and supporting early pregnancy development. This study aimed to identify miRNA plasmatic levels in cows at days 7 and 21 of pregnancy, based on the hypothesis that the amount of plasmatic miRNAs may vary during embryonic development due to the constant changes in gene expression occurring throughout this period. Fifteen nulliparous and primiparous Nellore cows with an average body weight of 478.67 ± 13.17 kg were used for the study, estrus synchronized followed by artificial insemination (AI). Blood samples were collected from the jugular vein of each animal, with two samplings performed for miRNA extraction on days 7 and 21 after AI. Additionally, ultrasonography was used to detect embryonic stages and monitor pregnancy. Based on the literature, 6 microRNAs (bta- miR-433, bta-miR-99a-3p, bta-miR-301b, bta-miR-26a, bta-miR-1249, bta-miR-101) were selected for analysis in pregnant females at 7 and 21 days (N=15), evaluated by RT-qPCR. Only miR-1249 showed a significant difference at a = 0,05 between the days of pregnancy (7 days vs. 21 days, P = 0.003). Despite the involvement of the studied miRNAs in important functions during pregnancy, only one of them (miR- 1249) showed significant differences. This enables the identification of plasma levels during days 7 and 21 of gestation and the identification of miRNAs that may be related to pregnancy and play important roles during embryonic development. Keywords: ribonucleic acid; gestation; molecular markers; plasma.