Effects of different fats on the competence of trophoblastic cells and bovine embryos to establish pregnancy

• Grant number: 22/06959-7
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): May 01, 2023
• Effective date (End): February 29, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Claudia Maria Bertan Membrive
• Grantee: Lucas de Oliveira Bezerra
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

In bovine herds, early embryonic mortality caused by failures in maternal-fetal recognition, between days 15 and 19 after fertilization, is one of the major causes of reproductive failure. Strategies that may favor maternal-fetal recognition during such a critical period become of fundamental economic interest. Such strategies aim to reduce the ability of the maternal endometrium to synthesize prostaglandin F2± (PGF2±) and/or maximize the conceptus-induced anti-luteolytic stimulus, including increased prostaglandin E2 (PGE2) synthesis. The use of different fatty acids can alter the proportion of PGE2 and PGF2± synthesized in trophoblast cells and embryos. CLA and AL are known to determine changes in the metabolic pathway of n-6 polyunsaturated fatty acid in the biosynthesis of eicosanoids, including prostaglandins (PG). Supplementation with such fatty acids in cell culture media has been reported to affect PG synthesis, however this effect has not yet been evaluated in bovine trophoblastic cells (CT1). In a recent study carried out by the group (Process FAPESP 2018/24168-1), the effects of treatment with CLA [cis-9, trans-11 and trans-10, cis-12] at different doses in the medium of cultivation of CT1. In this study, a reduction in PGF2± synthesis was observed in all groups treated with CLA (10, 20, 50 and 100 µM) with 24, 48 and 72 hours of culture compared to the control (0 µM). A higher PGE2/PGF2± ratio was also observed in all groups treated with CLA at 48 and 72 hours of culture compared to the control; and there were also changes in the abundance of transcripts involved in the biosynthesis of PGF2± and PGE2. In this study, different doses of CLA were also used in the in vitro production of embryos, during maturation and in vitro culture (MIV and CIV) or only in in vitro culture (IVC). We showed that the doses of 50 and 100 ¼M in the CIV increased the production of blastocysts hatched on D9. In view of the promising results obtained so far, we forward this proposal with the objective of proceeding with the aforementioned study, testing other types of fatty acids in the same biological models (CT1 and in vitro produced embryos), especially unconjugated linoleic acid (AL ; C18:26; omega 6), oleic acid (AO; C18:1; omega 9) and a mixture containing eicosapentaenoic acid (EPA; 20:53; omega 3) + docosahexaenoic acid (DHA; 22:63; omega 3). The hypothesis of this study is that supplementation with CLA, AL, AO or EPA + DHA increases the PGE2/PGF2± ratio and modifies the expression of transcripts involved in eicosanoid biosynthesis and maternal fetal recognition in CT1 and bovine embryos, in addition to favoring the level of DNA methylation in embryos. Thus, it becomes objective to evaluate the effects of supplementation with CLA, AL, AO or EPA + DHA on the PGE2/PGF2± ratio and on the expression of transcripts involved in prostaglandin biosynthesis (PTGER2, PTGER4, PTGES1, PLA2G10, PTGS2, PTGES2, AKR1B1 , AKR1C4) and maternal-fetal recognition (IFNT) in CT1 (Experiment 1); to compare the effects of supplementation with CLA, AL, AO or EPA + DHA in CIV on the PGE2/PGF2± ratio, on the expression of transcripts involved in prostaglandin biosynthesis (PTGER2, PTGER4, PTGES1, PLA2G10, PTGS2, PTGES2, AKR1B1, AKR1C4), on maternal-fetal recognition (IFNT) and DNA methylation level (DNMT1, DNMT3A, DNMT3B) in bovine embryos produced in vitro on D7 (Experiment 2). It is noteworthy that determining a comparison between both in vitro culture systems mentioned will make it possible to clarify what are the possible mechanisms of action CLA, AL, AO and EPA + DHA on the capacity of PG synthesis and the determination of success in pregnancy in trophoblast cells and embryos. Such information is fundamental to highlight the importance of greater production of PGE2 by the embryo and trophoblastic cells as a success factor for the establishment of pregnancy.