Developmental incompetency of denuded mouse oocytes undergoing maturation in vitro is ooplasmic in nature and is associated with aberrant Oct-4 expression.
BACKGROUND
Germinal vesicle (GV) oocytes constitute a potential resource but their developmental competence is questionable especially when surrounding cumulus cells are removed. The intercellular factors/mechanisms underlying such poor embryonic competence may originate at a nuclear and/or ooplasmic level.


METHODS
Immature or mature oocytes were obtained from three mouse strains following pregnant mare serum gonadotropin (PMSG) or PMSG+ human chorionic gonadotropin (hCG) treatment. Immature oocytes were denuded of cumulus cells prior to in vitro maturation. Pronuclear (PN) transfer was used to examine nuclear-ooplasmic interplay on resultant embryonic development and Oct-4 immuno-staining patterns.


RESULTS
Embryos arising from ooplasts of in vivo matured oocytes displayed significant increases in blastocyst formation rates and total blastomere numbers when compared to those created from ooplasts of denuded oocytes. Oct-4 staining was more pronounced and restricted to the inner cell mass (ICM) in blastocysts arising from the ooplasm of in vivo matured zygotes than in those created from denuded oocytes.


CONCLUSIONS
Developmental defect(s) appear to develop primarily in the ooplasm of oocytes that are denuded of their cumulus cells prior to in vitro maturation. Such oocytes result in embryos with poor developmental competence. These defects result in anomalies in cell number and Oct-4 expression during the morula-blastocyst developmental transition.
Chang
Hung Chi
HC
Program for In Vitro Fertilization, Reproductive Surgery and Infertility, New York University School of Medicine, New York, NY 10016, USA.
Liu
Hui
H
Zhang
John
J
Grifo
Jamie
J
Krey
Lewis C
LC
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004268:DNA-Binding Proteins / Q000378:metabolism*; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D005307:Fertilization in Vitro; D006064:Gonadotropins, Equine / Q000008:administration & dosage; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009028:Morula / Q000166:cytology / Q000378:metabolism; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D009866:Oogenesis; D014157:Transcription Factors / Q000378:metabolism*
D006063:Chorionic Gonadotropin; D004268:DNA-Binding Proteins; D006064:Gonadotropins, Equine; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors