Simulated physiological oocyte maturation has side effects on bovine oocytes and embryos

Author(s)

Razza, Eduardo M. ^[1] ; Pedersen, Hanne S. ^[2] ; Stroebech, Lotte ^[3] ; Fontes, Patricia K. ^[1] ; Kadarmideen, Haja N. ^[4] ; Callesen, Henrik ^[2] ; Pihl, Maria ^[5] ; Nogueira, Marcelo F. G. ^{[1, 6]} ; Hyttel, Poul ^[5]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Biosci, Dept Pharmacol, Dist Rubiao Jr S-N, BR-18618970 Sao Paulo - Brazil

^[2] Aarhus Univ, Dept Anim Sci, DK-8830 Tjele - Denmark

^[3] EmbryoTrans Biotech, DK-1851 Copenhagen C - Denmark

^[4] Tech Univ Denmark, Dept Bio & Hlth Informat, DK-2800 Lyngby - Denmark

^[5] Univ Copenhagen, Dept Vet & Anim Sci, Frederiksberg C - Denmark

^[6] Sao Paulo State Univ UNESP, Sch Sci & Languages, Dept Biol Sci, Ave Dom Antonio 2100, BR-19806900 Assis, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF ASSISTED REPRODUCTION AND GENETICS; v. 36, n. 3, p. 413-424, MAR 2019.
• Web of Science Citations: 1

Abstract

PurposeOocyte maturation is a complex process involving nuclear and cytoplasmic modulations, during which oocytes acquire their ability to become fertilized and support embryonic development. The oocyte is apparently primed for maturation during its development in the dominant follicle. As bovine oocytes immediately resume meiosis when cultured, it was hypothesized that delaying resumption of meiosis with cyclic nucleotide modulators before in vitro maturation (IVM) would allow the oocytes to acquire improved developmental competence.MethodsWe tested the Simulated Physiological Oocyte Maturation (SPOM) system that uses forskolin and 3-isobutyl-1-methylxanthine for 2h prior to IVM against two different systems of conventional IVM (Con-IVM). We evaluated the ultrastructure of matured oocytes and blastocysts and also assessed the expression of 96 genes related to embryo quality in the blastocysts.ResultsIn summary, the SPOM system resulted in lower blastocyst rates than both Con-IVM systems (309.1 vs. 35 +/- 8.7; 29 +/- 2.6 vs. 38 +/- 2.8). Mature SPOM oocytes had significantly increased volume and number of vesicles, reduced volume and surface density of large smooth endoplasmic reticulum clusters, and lower number of mitochondria than Con-IVM oocytes. SPOM blastocysts showed only subtle differences with parallel undulations of adjacent trophectoderm plasma membranes and peripherally localized ribosomes in cells of the inner cell mass compared with Con-IVM blastocysts. SPOM blastocysts, however, displayed significant downregulation of genes related to embryonic developmental potential when compared to Con-IVM blastocysts.ConclusionsOur results show that the use of the current version of the SPOM system may have adverse effects on oocytes and blastocysts calling for optimized protocols for improving oocyte competence. (AU)

• FAPESP's process: 13/05083-1 - Modulation of oocyte nuclear maturation and its effects on cumulus-oocyte complexes and bovine embryo production in vitro
• Grantee: Marcelo Fábio Gouveia Nogueira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/23409-9 - Differential gene expression, ultrastructural analysis and evaluation of the lipid profile of in vitro produced bovine blastocysts from oocytes matured conventionally or via SPOM system
• Grantee: Eduardo Montanari Razza
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/50533-2 - GIFT: genomic improvement of fertilization traits in Danish and Brazilian cattle
• Grantee: Marcelo Fábio Gouveia Nogueira
• Support Opportunities: Research Projects - Thematic Grants