Succinate and malate improve development of hamster eight-cell embryos in vitro: confirmation of viability by embryo transfer.
The in vitro development of hamster preimplantation embryos is supported by non-glucose energy substrates. To investigate the importance of embryonic metabolism, influence of succinate and malate on the development of hamster 8-cell embryos to blastocysts was examined using a chemically defined protein-free modified hamster embryo culture medium-2 (HECM-2m). There was a dose-dependent influence of succinate on blastocyst development; 0.5 mM succinate was optimal (85.1% +/- 3.9 vs. 54.5% +/- 3.5). In succinate-supplemented HECM-2m, blastocyst development was reduced by omission of lactate (68.5% +/- 7.2), but not pyruvate (85.8% +/- 6.2) or glutamine (84.1% +/- 2.1). Succinate along with either glutamine or lactate or pyruvate poorly supported blastocyst development (28%-58%). Malate also stimulated blastocyst development; 0.01 mM malate was optimal (86.3% +/- 2.8). Supplementation of both succinate and malate to HECM-2m supported maximal (100%) blastocyst development, which was inhibited 4-fold by the addition of glucose/phosphate. The mean cell numbers (MCN) of blastocysts cultured in succinate-supplemented HECM-2m was higher (28.3 +/- 1.1) than it was for those cultured in the absence of glutamine or pyruvate (range 20-24). The MCN was the highest (33.4 +/- 1.6) for blastocysts cultured in succinate-malate-supplemented HECM-2m followed by those in succinate (28.3 +/- 1.1) or malate (24.7 +/- 0.5) supplemented HECM-2m. Embryo transfer experiments showed that 29.8% (+/- 4.5) of transferred blastocysts cultured in succinate-malate-supplemented HECM-2m produced live births, similar (P > 0.1) to the control transfers of freshly recovered 8-cells (33.5% +/- 2.0) or blastocysts (28.9% +/- 3.0). These data show that supplementation of succinate and malate to HECM-2m supports 100% development of hamster 8-cell embryos to high quality viable blastocysts and that non-glucose oxidizable energy substrates are the most preferred components in hamster embryo culture medium.
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Center for Reproductive Biology and Molecular Endocrinology, Indian Institute of Science, Bangalore, India.
Seshagiri
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PB
D000818:Animals; D001755:Blastocyst / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D003470:Culture Media; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D005260:Female; D005947:Glucose / Q000494:pharmacology; D008293:Malates / Q000494:pharmacology*; D008297:Male; D008647:Mesocricetus; D009028:Morula / Q000502:physiology; D010710:Phosphates / Q000494:pharmacology; D011247:Pregnancy; D013386:Succinates / Q000494:pharmacology*; D019802:Succinic Acid
D003470:Culture Media; D008293:Malates; D010710:Phosphates; D013386:Succinates; C030298:malic acid; D019802:Succinic Acid; D005947:Glucose