Hyperinsulinemia during in vitro oocyte maturation changes gene expression of insulin signaling in bovine Day-8 embryos

Material and methods Embryos (n=120) were produced in vitro according to standardized methods and divided into three maturation groups with different insulin levels (High 10 μg/ml; Low 0.1 μg/ml and Zero=control). Gene expression data of D8BC was received through microarray studies after total-RNA-extraction at the EmbryoGENE-platform using a 2-colors-dye-swap design. Differentially expressed transcripts between control and insulin treated groups were searched by using an empirical Bayes moderated t-test in the ‘limma-package’ of R and defined as having a 1.5-fold change difference and p<0.05. Data was analyzed using IPA (www.ingenuity. com) to construct an overview over the insulin signaling pathway. Results Both genes associated with insulin resistance (PSMD4; PSMC1; MAP2K2) and its countermeasures (ADIPOR2; INSIG1) were up-regulated by insulin treatment.