Diets enriched in PUFAs at an early postimplantation stage prevent embryo resorptions and impaired mTOR signaling in the decidua from diabetic rats.

Maternal diabetes increases the risk of embryo resorptions and impairs embryo development. Decidualization is crucial for embryo development and regulated by mTOR signaling. However, little is known about how maternal diabetes affects the decidua at early postimplantation stages and whether dietary treatments enriched in polyunsaturated fatty acids (PUFAs) can prevent decidual alterations. Here, we determined resorption rates, decidual mTOR pathways and markers of decidual function and remodeling in diabetic rats fed or not with diets enriched in PUFAs exclusively during the early postimplantation period. Pregestational streptozotocin-induced diabetic Albino Wistar rats and controls were fed or not with diets enriched in 6% sunflower oil or 6% chia oil (enriched in n-6 or n-3 PUFAs, respectively) on days 7, 8 and 9 of pregnancy and evaluated on day 9 of pregnancy. Maternal diabetes induced an 11-fold increase in embryo resorptions, which was prevented by both PUFAs-enriched diets despite no changes in maternal glycemia. The activity of mTOR pathway was decreased in the decidua from diabetic rats, an alteration prevented by the PUFAs-enriched diets. PUFAs-enriched diets prevented increased expression of Foxo1 (a negative regulator of mTOR) and reduced expression of miR-21 (a negative regulator of Foxo1). These diets also prevented reduced markers of decidual function (leukemia inhibitory factor and IGFBP1 expression and MMPs activity) in diabetic rat decidua. We identified the early post implantation as a crucial stage for pregnancy success, in which dietary PUFAs can protect diabetic pregnancies from embryo resorptions, decidual mTOR signaling impairments, and altered markers of decidual function and remodeling.