RNA-seq of Oryctolagus cuniculus day-6 embryos
Infertility is a reproductive system disorder defined by the World Health Organization as 'the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse'. Currently, around 15% of couples worldwide are affected by this condition and, for a significant number of them, assisted reproductive technology (ART) provides a helpful solution. Indeed, the number of children born using these methods exceeds 10 million.In this context, the outcome of in vitro embryo culture has improved over the last decades, with many chemical formulations and physical platforms being developed to support it. Today it is known that the biophysical and chemical cues of the microenvironments impart significant spatiotemporal effects on embryonic development. However, current embryo culture techniques still have limitations, as they are unable to fully replicate the dynamic conditions of the reproductive tract in vitro. This suboptimal environment prompts mammalian embryos to display significant developmental reprogramming, resulting in distinct epigenetic and phenotypic variations at pre- and postnatal stages.Based on previous studies, we have hypothesized that, by mimicking an oviductal environment in vitro, the embryonic gene expression and the post-natal growth would more closely resemble those of naturally conceived (NC) animals. To create a culture environment to mimic the oviduct, we chose the rabbit as an animal model given its phylogenetic closeness to humans, the size of its oviducts, and its high reproductive performance. The main objective of this study was to evaluate the effect of an ECM hydrogel from DC rabbit oviducts (OviECM) used as a substrate for in vitro culture of embryos, compared to standard culture conditions. We aimed to assess its value in maintaining early embryonic development and, ultimately, the potential epigenetic and phenotypic changes induced in the embryos and the offspring.