Glucose and Pyruvate Metabolism of Preimplantation Goat Blastocysts followingIn VitroFertilization and Parthenogenetic Activation

Abstract

The energy metabolism of preimplantation embryos can be used to predict viability and postimplantation development. Although preimplantation development and mean blastocyst cell numbers of goat in vitro-fertilized (IVF) embryos and chemically activated parthenogenotes are comparable, mammalian parthenogenotes are not viable, with most dying shortly after implantation. The objective of this study was to compare glucose and pyruvate metabolism of IVF goat blastocysts with that of parthenogenetic blastocysts developing from chemically activated oocytes. Embryos derived from IVF and parthenogenotes produced by exposing oocytes to either ionomycin or ethanol followed by 6-dimethylaminopurine (6-DMAP) were cultured in G1.2/G2.2 sequential culture media. Metabolism was determined for individual blastocysts using [5-3H]glucose and [2-14C]pyruvate to determine glycolytic and Kreb's cycle activity, respectively. Data were analyzed by ANOVA. A significantly higher percentage of activated oocytes underwent cleavage and developed to the blastocyst stage compared to IVF oocytes (p < 0.05). There was no significant difference in glucose or pyruvate metabolism between IVF and parthenogenetically activated blastocysts. Mean glucose metabolism through glycolysis was 154.9 +/- 29.1, 130.3 +/- 17.1, and 129 +/- 16.5 pmol/embryo/3 h for IVF, ethanol-activated, and ionomycin-activated blastocysts, respectively. Mean pyruvate metabolism through the Kreb's cycle was 28.1 +/- 8.0, 15.8 +/- 4.2, and 24.4 +/- 4.4 in pmol/embryo/3 h for IVF, ethanol-activated, and ionomycin-activated blastocysts, respectively. Our results suggest that known differences in postimplantation development observed in IVF versus parthenogenetic embryos cannot be attributed to differences in pyruvate or glucose metabolism in the preimplantation blastocysts. Thus, these activation protocols result in embryos capable of appropriate regulation of key metabolic enzymes.

The ART of selecting the best embryo: A review of early embryonic mortality and bovine embryo viability assessment methods

“…In 1980, many researchers demonstrated the importance of glucose levels and developmental success: Higher glucose uptake correlated with successful development in bovine embryos (Takahashi and First, ), and Day‐10 cattle blastocysts developed better, both in culture and in vivo following transfer, if elevated glucose levels were observed (Renard et al, ). Glucose uptake, measured using noninvasive fluorometric techniques, was also shown to be significantly higher in viable mouse embryos that developed into live fetuses compared to their nonviable counterparts (Gardner and Leese, ), which was in agreement with a study looking at glucose metabolism of caprine embryos (Ongeri and Krisher, ). Previous animal studies have also consistently correlated higher glucose uptake around Day 4 or 5 of culture with viability (Gott et al, ; Gardner et al, ).…”

“…On the one hand, bovine embryos that developed to the blastocyst stage utilized more pyruvate and lactate in early preimplantation development (Rieger et al, ; Takahashi and First, ), whereas others reported that pyruvate and lactate are not required at this stage of development (Biggers et al, ; Rosenkrans et al, ). Goats show a pattern of pyruvate uptake similar to cattle embryos in early preimplantation development (Ongeri and Krisher, ), whereas sheep utilize pyruvate relatively constantly up to the morula stage, and then significantly increase its rate of uptake through the blastocyst stage (Butler and Williams, ; Gardner et al, ). Pyruvate uptake rates in the preimplantation embryo remain controversial in humans: some reports indicate that embryos that develop to the blastocyst stage had consistently higher pyruvate uptake than those that did not (Gott et al, ; Gardner et al, ; Seli et al, ), whereas others reported lower pyruvate uptake in 2–8‐cell embryos in relation to viability and pregnancy (Conaghan et al, ; 1993b).…”

Species and embryo genome origin affect lipid droplets in preimplantation embryos

“…In the present experiment, there is also observed significantly higher accumulation of lipids in b.PA blastocysts when compared to b.IVF counterparts. Studies on other species showed that parthenogenetic activation does not affect glucose metabolism in goat blastocysts (Ongeri and Krisher, 2001), whereas it dysregulates lipid metabolism (Pu et al, 2020). We also observed higher lipid content in PA blastocysts.…”

Role of AMPK throughout meiotic maturation in the mouse oocyte: Evidence for promotion of polar body formation and suppression of premature activation

“…This is not unprecedented, since other protein kinase inhibitors have been shown to promote this developmental response. For example, a wide range of studies have shown that the general kinase inhibitor 6-dimethylaminopurine is an effective inducer of parthenogenesis in oocytes of many mammalian species, including mouse (Szllosi et al, 1993;Liu et al, 1997;Nakasaka et al, 2000), rat (Jiang et al, 2002;Sano et al, 2009), cat (Yin et al, 2007), rabbit (Liu et al, 2002), pig (Leal and Liu, 1998;Jilek et al, 2001), bovine (Winger et al, 1997;Liu et al, 1998), sheep (Loi et al, 1998;Choi et al, 2004;Alexander et al, 2006), goat (Ongeri and Krisher, 2001), camel (Wani, 2008), rhesus monkey (Mitalipov et al, 2001), and human (Nakagawa et al, 2001). This is due in large measure to interruption of maturation promoting factor (MPF) activity, which is required to maintain MII arrest and is regulated by mitogen-activated protein kinase (Fan and Sun, 2004).…”