title: Anomalous oxygen consumption in porcine somatic cell nuclear transfer embryos.
abstract: Oxygen consumption reflects overall metabolic activity of mammalian embryos. We measured oxygen consumption in individual porcine somatic cell nuclear transfer (SCNT) and in vitro-fertilized (IVF) embryos by modified scanning electrochemical microscopy. Oxygen consumption in IVF embryos rapidly increased at day 5 of the blastocyst stage (D5BL). IVF embryos that consumed >0.81 x 10(14)/mol sec(-1) of oxygen at D5BL exhibited significantly higher hatching and hatched rates at D7BL, whereas D5BL SCNT embryos using porcine fetal fibroblasts did not show an increase in oxygen consumption until D7BL. The numbers of inner cell mass and trophectoderm (TE) cells and incidence of apoptosis did not significantly differ between IVF and SCNT embryos at D5BL. At D7BL, a significant lower number of TE cell and higher incidence of apoptosis were observed in SCNT than in IVF embryos; this significantly correlated with their oxygen consumption at D5BL. Use of cumulus cells as donor cells neutralized the low oxygen consumption in SCNT embryos at D5BL, regardless of the difference between the recipient cytoplasm and donor nucleus. Some of SCNT embryos at D7BL were retrieved the hatching completion and were improved the number of TE cell and apoptosis incidence by using cumulus cells. Thus, anomalous oxygen consumption in porcine SCNT embryos at D5BL could be sign of limited hatchability, which may be responsible for the low TE cell number and high apoptosis incidence.
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan. s0sugimr@nlbc.go.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sugimura
authors.forename: Masaki
authors.initials: M
authors.lastname: Yokoo
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yamanaka
authors.forename: Manabu
authors.initials: M
authors.lastname: Kawahara
authors.forename: Satoru
authors.initials: S
authors.lastname: Moriyasu
authors.forename: Takuya
authors.initials: T
authors.lastname: Wakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Eimei
authors.initials: E
authors.lastname: Sato
mesh_terms: D000818:Animals; D017209:Apoptosis; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002467:Cell Nucleus / Q000502:physiology*; D002478:Cells, Cultured; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro; D051379:Mice; D008810:Mice, Inbred C57BL; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D013552:Swine
chemical_list: D010100:Oxygen