Oocyte mitochondria: strategies to improve embryogenesis.
Mitochondria play a central role to provide ATP for fertilization and preimplantation embryo development in the ooplasm. The mitochondrial dysfunction of oocyte has been proposed as one of the causes of high levels of developmental retardation and arrest that occur in preimplantation embryos generated using Assisted Reproductive Technology. Cytoplasmic transfer (CT) from a donor to a recipient oocyte has been applied to infertility due to dysfunctional ooplasm, with resulting pregnancies and births. However, neither the efficacy nor safety of this procedure has been appropriately investigated. In order to improve embryogenesis, we observed the mitochondrial distribution in ooplasma under the several conditions using mitochondrial GFP-transgenic mice (mtGFP-tg mice) in which the mitochondria are visualized by GFP. In this report, we will present our research about the mitochondrial distribution in ooplasm during early embryogenesis and the fate of injected donor mitochondria after CT using mtGFP-tg mice. The mitochondria in ooplasm from the germinal vesicle stage to the morula stage were accumulated in the perinuclear region. The mitochondria of the mtGFP-tg mouse oocyte transferred into the wild type mouse embryo could be observed until the blastocysts stage, suggesting that the mtGFP-tg mice oocyte is very useful for visual observation of the mitochondrial distribution in the oocyte, and that the aberrant early developmental competences due to the oocyte mitochondrial dysfunction may be overcome by transferring the "normal" mitochondria.
Nagai
Seiichiro
S
Department of Obstetrics and Gynecology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Tamaho, Nakakoma. naseiichi@hotmail.com
Mabuchi
Tadashi
T
Hirata
Shuji
S
Shoda
Tomoko
T
Kasai
Tsuyoshi
T
Yokota
Sadaki
S
Shitara
Hiroshi
H
Yonekawa
Hiromichi
H
Hoshi
Kazuhiko
K
D000818:Animals; D002478:Cells, Cultured; D003593:Cytoplasm; D004622:Embryo, Mammalian / Q000166:cytology / Q000648:ultrastructure; D047108:Embryonic Development; D005260:Female; D049452:Green Fluorescent Proteins; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D008845:Microinjections; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000502:physiology / Q000637:transplantation* / Q000648:ultrastructure; D009865:Oocytes / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure*; D027724:Reproductive Techniques, Assisted
D049452:Green Fluorescent Proteins