title: Bovine embryo survival under oxidative-stress conditions is associated with activity of the NRF2-mediated oxidative-stress-response pathway.
abstract: In present study, we sought to examine the ability of preimplantation bovine embryos to activate the NF-E2-related factor 2 (NRF2)-mediated oxidative-stress response under an oxidative stress environment. In vitro 2-, 4-, 8-, 16-cell-, and blastocyst-stage embryos were cultured under low (5%) or high (20%) oxygen levels. The expression of NRF2, KEAP1 (NRF2 inhibitor), antioxidants downstream of NRF2, and genes associated with embryo metabolism were analyzed between the embryo groups using real-time quantitative PCR. NRF2 and KEAP1 protein abundance, mitochondrial activity, and accumulation of reactive oxygen species (ROS) were also investigated in blastocysts of varying competence that were derived from high- or low-oxygen levels. The expression levels of NRF2 and its downstream antioxidant genes were higher in 8-cell, 16-cell, and blastocyst stages under high oxygen tension, whereas KEAP1 expression was down-regulated under the same conditions. Higher expression of NRF2 and lower ROS levels were detected in early (competent) blastocysts compared to their late (noncompetent) counterparts in both oxygen-tension groups. Similarly, higher levels of active nuclear NRF2 protein were detected in competent blastocysts compared to their noncompetent counterparts. Thus, the survival and developmental competence of embryos cultured under oxidative stress are associated with activity of the NRF2-mediated oxidative stress response pathway during bovine pre-implantation embryo development.
authors: Ahmed
authors: A
authors: Amin
authors: Ahmed
authors: A
authors: Gad
authors: Dessie
authors: D
authors: Salilew-Wondim
authors: Sigit
authors: S
authors: Prastowo
authors: Eva
authors: E
authors: Held
authors: Michael
authors: M
authors: Hoelker
authors: Franca
authors: F
authors: Rings
authors: Ernst
authors: E
authors: Tholen
authors: Christiane
authors: C
authors: Neuhoff
authors: Christian
authors: C
authors: Looft
authors: Karl
authors: K
authors: Schellander
authors: Dawit
authors: D
authors: Tesfaye
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002417:Cattle; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics; D047108:Embryonic Development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D051267:NF-E2-Related Factor 2; D017382:Reactive Oxygen Species