GSE127889
Good quality day 7 embryos display disturbed cellular functions during post-hatching development when oocytes were matured under lipotoxic conditions: novel insights from a bovine embryo-transfer model
Objective: To study post-hatching development after transfer of morphologically good quality embryos that survived in vitro maturation under lipolytic conditions using a well-established and recognized bovine model. Design: prospective study with a crossover design. Setting: research laboratory. Animals: 8 healthy multiparous non-lactating Holstein cows used in repeated embryo transfers. Intervention(s): Bovine cumulus oocyte complexes (COCs) were in vitro matured in the presence of either 1) a combination of elevated pathophysiological concentration of palmitic acid (PA) and physiological concentrations of stearic acid (SA) and oleic acid (OA) (HIGH PA), or 2) physiological concentrations of PA, SA and OA (BASAL). Matured oocytes were fertilized and cultured in FA-free conditions until day 7.7 p.i. Equal proportions of normal and expanded blastocysts were subsequently transferred to synchronized cows. Conceptuses were transcervically recovered 7 days after the transfer. Main Outcome Measure(s): Recovered embryos were morphologically assessed and dissected into embryonic disc (ED) and extraembryonic tissue (EXT). Samples of EXT were used for analysis of interferon-t (IFN-t) secretion and measurement of cellular metabolic activity. ED and EXT samples were subjected to RNA sequencing in order to evaluate the genome wide transcriptome patterns of recovered day 14 embryos. Results: Recovered embryos resulting from metabolically compromised oocytes were retarded in growth or less elongated than their control counterparts. Furthermore, they exhibited a decrease in glucose consumption and lactate production. Importantly, lipolytic conditions resulted in reduced capacity of the embryo to signal its presence to the mother through IFN-t secretion. The transcriptome profile was altered in the recovered embryos with main effects in pathways related to redox-regulating mechanisms, apoptosis, cellular growth, interaction and differentiation, energy metabolism, and epigenetic mechanisms. Overall design: A total of 53 samples (extraembryonic tissue (EX) and embryonic discs (ED)) were used for RNA/DNA extraction, representative for the pool of recovered day 14 embryos, the embryo morphology, the recipient cows (embryos from one of the eight cows were excluded for RNA sequencing) and replicates.