Effects of dietary selenium on placental development, antioxidant status and the expression of vascular endothelial growth factors in sheep

Abstract

This study investigated the effects of maternal selenium (Se) supplementation on placental development, antioxidant status and the expression of vascular endothelial growth factors (VEGFs) in sheep. A total of 80 Hu ewes (body weight: 57.45 ± 4.72 kg, age: 0.83 ± 0.15 yrs.) were randomly assigned to a control (basal diet) or Se group (0.5 mg Se/kg DM) for 150 d. Dietary Se supplementation increased the litter birth weight, average birth weight, Se concentrations in maternal blood (120 d) and placental tissues, placental weight, the number and weight of cotyledons, and the number of umbilical artery and vein branches. Hematoxylin and Eosin (H&E) staining revealed that dietary Se could increase the number of placental trophoblast cells. Additionally, Se supplementation improved the total antioxidant capacity (T-AOC) and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and decreased the content of malondialdehyde (MDA) in cotyledons. Dietary Se supplementation increased the mRNA and protein expression associated with antioxidant pathway, selenoproteins, and VEGFs and its receptors in cotyledons. The results were further verified by immunohistochemistry. In conclusion, maternal Se supplementation was associated with increased placental size and offspring birth weight by increasing trophoblast cell numbers, cotyledon growth, and umbilical vessel branching, while boosting antioxidant capacity and upregulating selenoproteins and VEGF pathways in cotyledons.