title: Improvement of porcine oocytes with low developmental ability after fusion of cytoplasmic fragments prepared by serial centrifugation.
abstract: We have shown in pigs that oocytes denuded of cumulus cells at 24 h of in vitro maturation culture and subsequently matured for a total of 46 h (DO24 oocytes) have lower cytoplasmic maturity than those matured with cumulus cells for 46 h and then denuded (DO46 oocytes). In the present study, DO24 zona-free oocytes were fused with one (1C) or two (2C) cytoplasmic fragments produced by serial centrifugation ("centri-fusion") of DO46 oocytes (DO24+1C and DO24+2C oocytes, respectively). Groups of (1) DO46 (a control), (2) DO24, (3) DO24+1C and (4) DO24+2C oocytes were partheno-activated by an electrical pulse or fertilized in vitro and subsequently cultured for 6 days. In the fused groups, female pronucleus (FPN) formation rates were higher than that in the DO24 group after parthenogenetic activation (PA); however, the blastocyst rates were intermediate between those of the control and DO24 groups. After in vitro fertilization, the male pronucleus (MPN) formation rates in the fused groups were similar to that in the control group and higher than that in the DO24 group; the normal fertilization rate in the DO24+2C group was higher than that in the DO24 group and similar to that in the control group, resulting in significantly higher blastocyst rates in the DO24+2C and control groups than that in the DO24 group. These results suggest that centri-fusion using ooplasm from fully matured DO46 oocytes can offer a potentially novel approach for restoration of cytoplasmic maturity to oocytes with low developmental ability and subsequent improvement of fertilization and developmental competence.
authors.affiliation: Animal Resource Science Center, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Ibaraki 319-0206, Japan.
authors.forename: Nguyen
authors.initials: N
authors.lastname: Viet Linh
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kikuchi
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakai
authors.forename: Junko
authors.initials: J
authors.lastname: Noguchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaneko
authors.forename: Thanh Quang
authors.initials: TQ
authors.lastname: Dang-Nguyen
authors.forename: Naoki
authors.initials: N
authors.lastname: Maedomari
authors.forename: Bui Xuan
authors.initials: BX
authors.lastname: Nguyen
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
authors.forename: Noboru
authors.initials: N
authors.lastname: Manabe
mesh_terms: D000818:Animals; D002458:Cell Fractionation / Q000379:methods; D002459:Cell Fusion / Q000379:methods; D002478:Cells, Cultured; D002498:Centrifugation / Q000379:methods; D003593:Cytoplasm / Q000737:chemistry* / Q000502:physiology / Q000637:transplantation*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D009866:Oogenesis / Q000502:physiology; D010312:Parthenogenesis / Q000502:physiology; D013552:Swine / Q000502:physiology