title: Murine pre-embryo oxygen consumption and developmental competence.
abstract: OBJECTIVE
  In search for a new marker of preimplantation embryo viability the present study investigated oxygen consumption of individual cleavage stage murine embryos, and evaluated the predictive value regarding subsequent development to expanded blastocysts.
  
  
  METHODS
  In all, 248 embryos were investigated from 2 cell stage until blastocyst stage with individual measurement of oxygen consumption and recording of developmental stage. Cleavage stage embryos and morula were divided in groups according to their oxygen consumption, and odds ratios (OR) for subsequent development to expanded blastocyst were calculated.
  
  
  RESULTS
  Cleavage stage (2-8 cell) individual oxygen consumption was 0.16-0.20 nl O(2) h(-1), with a significant increase to 0.21-0.23 nl O(2) h(-1) at the morula stage followed by a more than twofold increase for the expanded blastocyst 0.47 nl O(2) h(-1). A significantly higher chance of reaching the expanded blastocyst stage was found in 4-cell embryos with high oxygen consumption, than embryos with low consumption (OR 2.25, 95% CI 1.04-4.90). Among 2-cell embryos the chance of low and high consumers was not significantly different. The method used in the present study somewhat compromised embryo development (51% blastocyst rate) compared to controls (80% blastocystrate) which could make our results less robust.
  
  
  CONCLUSIONS
  Preliminary data from the present study suggest that oxygen consumption in cleavage stage embryos may be an indicator, but a not a strong predictor, of subsequent development to expanded blastocysts.
authors.affiliation: The Fertility Clinic, Department of Obstetrics and Gynaecology, Aarhus University Hospital Skejby Sygehus, Brendstrupgaardsvej, 8200, Arhus N, Denmark. lars.ottosen@ki.au.dk
authors.forename: Lars D M
authors.initials: LD
authors.lastname: Ottosen
authors.forename: Johnny
authors.initials: J
authors.lastname: Hindkjaer
authors.forename: Svend
authors.initials: S
authors.lastname: Lindenberg
authors.forename: Hans Jakob
authors.initials: HJ
authors.lastname: Ingerslev
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002970:Cleavage Stage, Ovum / Q000378:metabolism; D047108:Embryonic Development; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011247:Pregnancy
chemical_list: D010100:Oxygen