In vitromaturation alters gene expression in bovine oocytes

Abstract

Gene expression profiling of in vivo- and in vitro-matured bovine oocytes can identify transcripts related to the developmental potential of oocytes. Nonetheless, the effects of in vitro culturing oocytes are yet to be fully understood. We tested the effects of in vitro maturation on the transcript profile of oocytes collected from Bos taurus indicus cows. We quantified the expression of 1488 genes in in vivo- and in vitro-matured oocytes. Of these, 51 genes were up-regulated, whereas 56 were down-regulated (≥2-fold) in in vivo-matured oocytes in comparison with in vitro-matured oocytes. Quantitative real-time polymerase chain reaction (PCR) of nine genes confirmed the microarray results of differential expression between in vivo- and in vitro-matured oocytes (EZR, EPN1, PSEN2, FST, IGFBP3, RBBP4, STAT3, FDPS and IRS1). We interrogated the results for enrichment of Gene Ontology categories and overlap with protein-protein interactions. The results revealed that the genes altered by in vitro maturation are mostly related to the regulation of oocyte metabolism. Additionally, analysis of protein-protein interactions uncovered two regulatory networks affected by the in vitro culture system. We propose that the differentially expressed genes are candidates for biomarkers of oocyte competence. In vitro oocyte maturation can affect the abundance of specific transcripts and are likely to deplete the developmental competence.

In vivo and in vitro maturation of rabbit oocytes differently affects the gene expression profile, mitochondrial distribution, apoptosis and early embryo development

“…Paradoxically, in the present study we found that Gapdh mRNA transcripts decreased slightly in CCs after in vivo maturation compared with CCs from immature GV oocytes. These differences between experimental groups dissuaded us from using this gene as an internal control in the quantitative analysis of gene expression, in contrast with previous reports in dogs (Cho et al 2016), mice (Shao et al 2015) and humans (Ouandaogo et al 2012), but support previous findings in rabbit embryos (Arias-Á lvarez et al 2013a(Arias-Á lvarez et al , 2013b, mouse oocytes (Jeong et al 2005;Cui et al 2007) and bovine oocytes (Bermejo-Á lvarez et al 2010;Adona et al 2016). These controversial results indicate that the expression of GAPDH could differ among species and this deserves further investigation.…”

“…In recent years, several studies in animal models (Nivet et al 2013;Blaha et al 2015;Shao et al 2015) and humans (McKenzie et al 2004;Adriaenssens et al 2010;Assou et al 2010;Li et al 2015) have tried to identify candidate genes expressed in CCs that could be used as biomarkers of oocyte quality. In this sense, some studies have focused on identifying differences in gene expression between IVM and in vivo-matured cumulus-oocyte complexes (COCs) in many species, including dogs (Cho et al 2016), cattle (Tesfaye et al 2009;Adona et al 2016), mice (Cecconi et al 2010) and humans (Jones et al 2008;Ouandaogo et al 2012). The results from these studies show that the expression of transcripts in CCs and oocytes is altered by in vitro conditions, giving rise to developmentally incompetent oocytes.…”

Oxidative homeostasis in oocyte competence for in vitro embryo development

“…In the bovine species, this in vitro production technique of embryos has been applied on a large scale, aiming at the genetic improvement of the herd (Baldassarre et al, ; Zacarias et al, ). Despite its wide applicability since its inception, in vitro fertilization is not fully established and several issues still need to be resolved and procedures need to be optimized (Adona et al, ; Liang et al, ; Sirard, ).…”

Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production

“…Development rates obtained with in vitro maturation are, however, lower than those from in vivo maturation (Gilchrist, 2010). Therefore, many studies have been conducted to improve the efficiency of oocyte in vitro maturation (Adona et al, 2016;Lee et al, 2016). Several parameters, such as gaseous atmosphere, temperature, protein supplementation, growth factors and oocyte manipulation, may influence the embryo production process in vitro (Adona et al, 2008;Arat et al, 2016;Mingoti, Castro, Méo, Barretto, & Garcia, 2009).…”