Energy substrates and amino acids provided during in vitro maturation of bovine oocytes alter acquisition of developmental competence

Abstract

Energy substrates and amino acids were evaluated for supporting acquisition of developmental competence by bovine cumulus-oocyte complexes during in vitro maturation. The basic culture medium (Basic Medium-3) used for in vitro maturation of oocytes was modified to produce six media containing glucose or glutamine with lactate or pyruvate, or glucose + glutamine, or glucose + 11 amino acids; a seventh (control) medium was TCM199. All media contained polyvinyl alcohol, gonadotropins, epidermal growth factor and oestradiol. Following maturation, oocytes were incubated in medium TALP for fertilisation, then cumulus cells were removed and presumptive embryos cultured for 48 h in a chemically defined medium (HECM-6) followed by 120 h in medium TCM199 + bovine calf serum. Six substrate treatments yielded similar first cleavage responses (66-78%) at 72 h post-insemination; however, blastocyst development at 192 h varied significantly. Oocytes matured in medium with glucose + 11 amino acids gave the best blastocyst development: 21% of inseminated oocytes or 25% of 2-cell embryos. Cumulus expansion in HECM-6 required glucose with either glutamine, 11 amino acids or lactate, or glutamine + lactate. We conclude that (1) the type of energy substrate or nutrient supplied during in vitro maturation of oocytes profoundly affects subsequent developmental competence; (2) oocyte maturation in simple medium containing glucose with lactate or 11 amino acids or glutamine, or lactate + glutamine, can support development equally as well as the complex medium, TCM199; and (3) media supporting at least moderate cumulus expansion during oocyte maturation also support subsequent blastocyst development.

The pivotal role of glucose metabolism in determining oocyte developmental competence

“…AR, aldose reductase; ECM, extracellular matrix; G6PDH, glucose-6-phosphate dehydrogenase; GFPT, glucosamine:-fructose acetyl transferase; HAS2, hyaluronan synthase 2; HK, hexokinase; OGT, O-linked glycosylation transferase; PFK, phosphofructokinase; SDH, sorbitol dehydrogenase. developmental capacity of oocytes (Krisher & Bavister 1998, Rose-Hellekant et al 1998, Zheng et al 2001. However, concentrations too low (!2.3 mM glucose) or high (O10 mM glucose) are detrimental to oocyte development (Table 1).…”

“…However, concentrations too low (!2.3 mM glucose) or high (O10 mM glucose) are detrimental to oocyte development (Table 1). Culturing bovine COCs in medium containing physiological or lower concentrations of glucose (1.5-2.3 mM glucose) can lead to perturbations in the completion of nuclear maturation (Sutton-McDowall et al 2005) and poor embryo development post-fertilisation (Rose-Hellekant et al 1998, Eppig et al 2000, Ali & Sirard 2002, Ali et al 2003. van de Sandt et al (1990) compared the developmental outcomes of mouse COC after IVM in different base medium, with oocytes cultured in Waymouth medium having improved blastocyst development and increased cell numbers than oocytes cultured in media containing significantly lower glucose levels, seemingly contradicting the notion that high glucose levels are detrimental to oocyte developmental competence.…”

“…Suboptimal culture conditions during IVM result in reduced blastocyst development post-fertilisation (van de Sandt et al 1990, Rose & Bavister 1992, Rose-Hellekant et al 1998. Moreover, it is becoming increasingly evident that the consequences of poor maternal health, such as diabetes, obesity and poor diet, all result in hyperglycaemic increases in intra-follicular glucose levels, and that this is associated with poor oocyte viability in mice (Moley et al 1998).…”

Effects of in vitro maturation of monkey oocytes on their developmental capacity

“…Energy substrates have been found to affect oocyte maturation and embryo development in a wide variety of mammals (McKiernan et al, 1991;Rose-Hellekant et al, 1998;Zheng et al, 2001c). Glucose, lactate and pyruvate are designated as the "energy substrate triad" in cellular metabolism (Bavister, 1995).…”

“…In rodents, domesticated animals and humans, oocyte maturation and embryo development can be profoundly influenced by the type of amino acid provided in the culture medium (Pinyopummintr and Bavister, 1996;Kito and Bavister, 1997;Rose-Hellekant et al, 1998;Devreker and Englert, 2000;Hong et al, 2004). Amino acids function as substrates for protein synthesis (true for most of the amino acids), energy substrates (e.g., glutamine), neurotransmitters, synaptic modulators, signal transducers (Martin et al, 2003), regulators of intracellular pH (Edwards et al, 1998) and organic osmolytes (e.g., glycine) (Palacin et al, 1998;Steeves and Baltz, 2005).…”