Effects of conjugated linoleic acid supplementation on trophoblastic cell culture and bovine embryos on the secretion and expression of transcripts involved in the prostaglandin E2 and F2± biosynthesis and the establishment of pregnancy

Abstract

In bovine herds the 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 failures. 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 PGF2 alpha synthesis by the maternal endometrium and/or maximize the anti-luteolytic stimulus induced by the concept. Conjugated linoleic acid (CLA), especially cis-9, trans-11 (c9, t11) and trans-10, cis-12 (t10, c12), is known to determine modifications in the metabolic pathway of n-6 polyunsaturated fatty acid in biosynthesis of eicosanoids, including prostaglandins (PG). The reduction in the production of PGF2 alpha together with the increase in the synthesis of PGE2 characterizes a beneficial condition to the establishment of the pregnancy. It has been reported that CLA supplementation in cell culture media affects PG synthesis, however such an effect has not been evaluated in bovine trophoblastic cells (CT1). The hypothesis of this study is that the CLA supplementation of CT1 cell culture media (Experiment 1) and bovine embryos produced in vitro (Experiment 2) increases the synthesis of PGE2 and reduces the synthesis of PGF2 by altering the expression of transcripts involved in the biosynthesis of eicosanoids and other processes that benefit the endometrial response determinant for the establishment of pregnancy. The aim is to determine the effects of CLA supplementation (a mixture of cis- and trans-9,11- and -10,12-octadecadienoic acid) in the in vitro culture of CT1 cells (Experiment 1) and the in vitro production of bovine embryos (Experiment 2) on the synthesis of PGE2 and PGF2 alpha and on the expression of transcripts for the synthesis of PG (PTGER2, PTGER4, PTGES, PLA2G10, PTGS2, PTGES2, AKR1B1, AKR1C4); of factors involved in placental angiogenesis and factors favoring increased blood flow (PIGF, VEGF); factors that benefit placental implantation and remodeling (MMP2, MMP9, TIMP1, TIMP2 and TIMP3); as well as the interferon-tau synthesis (IFNT), determinant for maternal-fetal recognition; and placental hormones (PAGs, TKDPs, CSH1). Considering the impact of the economic losses caused by the early embryonic mortality in bovine females on the profitability of cattle breeding enterprises in the breeding phase in beef cattle females, if a beneficial effect of CLA supplementation on CT1 cells and / or in vitro-produced bovine embryos is demonstrated, this ideia will allow the determination of strategies in the field that can reduce early embryonic mortality and thus improve design rates in fixed-time artificial insemination (FTAI) and fixed-time embryo transfer (FTET) programs. (AU)