Impact of Bovine Oocyte Maturation Media on Oocyte Transcript Levels, Blastocyst Development, Cell Number, and Apoptosis1

Abstract

The objectives were 1) to investigate the effects of oocyte maturation in serum-free and amino acid-supplemented defined media on oocyte transcript levels, blastocyst cell number, and apoptosis; 2) to investigate the influence of oocyte maturation culture atmosphere on blastocyst development, total cell number, and apoptosis; and 3) to examine the influence of epidermal growth factor (EGF) during oocyte maturation on blastocyst cell number and apoptosis. The results demonstrate that blastocysts derived from in vitro maturation, fertilization, and embryo culture protocols undergo apoptosis but that apoptotic levels are not greatly influenced by the oocyte maturation environment. Amino acid supplementation of oocyte maturation media was associated with enhanced developmental frequencies, increased blastocyst cell number, and elevated oocyte maternal mRNA levels. Oocyte maturation with supplemented synthetic oviduct fluid medium (cSOFMaa) resulted in blastocyst cell numbers comparable to those observed with Tissue Culture Medium 199 + newborn calf serum. Blastocyst development was reduced following oocyte maturation under a 5% CO(2), 7% O(2), 88% N(2) culture atmosphere. EGF supplementation of oocyte maturation medium resulted in a concentration-dependent increase in blastocyst development but did not influence blastocyst total cell number or apoptosis. Our findings indicate that cSOFMaa medium is an effective base medium for bovine oocyte maturation.

Bovine oocytes and early embryos express Staufen and ELAVL RNA-binding proteins

“…Approaches in this research area have included studies directly comparing the levels of "marker" gene expression, also variations in embryo metabolism between in vitro and in vivo derived preimplantation embryos and most recently epigenetic re-programming as signified by variation in DNA methylation patterns (Brevini-Gandolfi et al, 1999;De Sousa et al, 1998;Ecker et al, 2004;Knijn et al, 2005;Leese, 2002;Mann et al, 2004;Watson et al, 2000;Wrenzycki et al, 1999;Wrenzycki et al, 2005).…”

Ammonium exposure and pyruvate affect the amino acid metabolism of bovine blastocysts in vitro

“…It is not surprising, therefore, that supplementing embryo culture medium with a mixture of amino acids reduces cultureinduced metabolic perturbations and associated loss of viability in murine blastocysts (Lane & Gardner 1998) and overcomes developmental blocks in their leporine counterparts (Liu et al 1996). It has also been suggested that in vitro produced embryos should be exposed to amino acids as early as the oocyte stage, as this increases oocyte maternal mRNA levels and promotes preimplantation development (Watson et al 2000). In support of this opinion, it is notable that a brief exposure of zygotes to amino acid-free conditions depresses their developmental capacity and blastocyst cell numbers (Gardner & Lane 1996).…”

The effect of nutrition and metabolic status on the development of follicles, oocytes and embryos in ruminants

“…In cattle, LH has been shown to increase glutamine oxidative metabolism by oocytes and COCs (Zuelke and Brackett, 1993). Furthermore, the addition of glutamine to bovine IVM media promoted the nuclear maturation of oocytes (Bilodeau-Goeseels, 2006), although supplementation of defined IVM media with nonessential and essential amino acids increased the levels of maternal mRNA in the oocytes and enhanced embryo development (Watson et al, 2000). Finally, Hemmings et al (2012) quantified the amino-acid profiles (i.e.…”