Bovine embryo survival under oxidative‐stress conditions is associated with activity of the NRF2‐mediated oxidative‐stress‐response pathway. Issue 6 (21st March 2014)

• Record Type: Journal Article
• Authors: Amin, Ahmed; Gad, Ahmed; Salilew‐Wondim, Dessie; Prastowo, Sigit; Held, Eva; Hoelker, Michael; Rings, Franca; Tholen, Ernst; Neuhoff, Christiane; Looft, Christian; Schellander, Karl; Tesfaye, Dawit
• Is Part Of: Molecular reproduction and development. Volume 81:Issue 6(2014:Jun.)
• Page Start: 497
• Page End: 513
• Publication Date: 2014-03-21
• Subjects: Reproduction -- Periodicals; Molecular biology -- Periodicals; Molecular genetics -- Periodicals; Embryology -- Periodicals; 571.8
• DOI: 10.1002/mrd.22316
• Languages: English
• ISSNs: 1040-452X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>SUMMARY</title> <sec id="mrd22316-sec-0001" sec-type="section"> <p>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 <italic>NRF2</italic>, <italic>KEAP1</italic> (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 <italic>NRF2</italic> and its downstream antioxidant genes were higher in 8‐cell, 16‐cell, and blastocyst stages under high oxygen tension, whereas <italic>KEAP1</italic> expression was down‐regulated under the same conditions. Higher expression of <italic>NRF2</italic> 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. <italic>Mol. Reprod. Dev. 81: 497–513, 2014. © 2014 Wiley Periodicals, Inc</italic>.</p> </sec> </abstract>