Embryo-luteal cells co-culture: an in vitro model to evaluate steroidogenic and prostanoid bovine early embryo-maternal interactions

摘要

The role of progesterone (P-4) and prostaglandins (PGs) in bovine early embryonic development and embryo-maternal crosstalk is almost unknown. Here, the in vitro steroidogenic (P-4) and prostanoid (PGE(2) and PGF(2 alpha)) interactions between bovine embryos and luteal cells (LC) were evaluated. In two experiments, embryos (n = 1.900) were either co-cultured with LC or cultured alone, from days 2 to 7 (day 0 = in vitro insemination). LC were also cultured alone, and medium was used as a control, all groups being cultured either with or without oil overlay of culture medium. Oil overlay of culture medium significantly decreased the amount of P-4, but not of PGE(2) and PGF(2 alpha) measured in culture medium. Embryos and LC had transcripts of genes coding for enzymes of the PGs (PTGS2, PGES, and PGFS) and P-4 (StAR, P450scc, and 3 beta-HSD) synthesis pathways, and produced P-4, PGF(2 alpha), and PGE(2) into culture medium. Co-culture with LC exerted an embryotrophic effect, significantly increasing blastocyst yield and quality. This indicates a possible direct effect of LC in early embryo development. Embryos did not exert a luteotrophic effect upon LC. This may indicate that early embryos (until day 7) probably do not exert influence in LC main function. It is suggested that production of P-4, PGE(2), and PGF(2 alpha) by early embryos may be associated to autocrine signaling leading to events in development and to paracrine signaling in the endometrium leading to local uterine receptivity.