title: Follicle-stimulating hormone affects metaphase I chromosome alignment and increases aneuploidy in mouse oocytes matured in vitro.
abstract: Follicle-Stimulating Hormone (FSH) at a wide range of doses is routinely added to culture media during in vitro maturation (IVM) of oocytes, but the effects on oocyte health are unclear. The suggestion that superovulation may cause aneuploidy and fetal abnormalities prompted us to study the potential role of FSH in the genesis of chromosomal abnormalities during meiosis I. Mouse cumulus-oocyte complexes (COCs) isolated from the antral follicles of unprimed, sexually immature B6CBF1 mice were cultured in increasing concentrations of FSH. Following culture, matured oocytes were isolated, spread, stained with DAPI, and the numbers of chromosomes counted. Significantly increased aneuploidy, arising during the first meiotic division, was observed in metaphase II oocytes matured in higher concentrations of FSH (> or =20 ng/ml). The effect of FSH on spindle morphology and chromosome alignment during metaphase I was then explored using immunocytochemistry and three-dimensional reconstruction of confocal sections. High FSH had no effect on gross spindle morphology but did alter chromosome congression during prometaphase and metaphase, with the spread of chromosomes across the spindle at this time being significantly greater in oocytes cultured in 2000 ng/ml compared with 2 ng/ml FSH. Analysis of three-dimensional reconstructions of spindles in oocytes matured in 2000 ng/ml FSH shows that chromosomes are more scattered and farther apart than they are following maturation in 2 ng/ml FSH. These results demonstrate that exposure to high levels of FSH during IVM can accelerate nuclear maturation and induce chromosomal abnormalities and highlights the importance of the judicious use of FSH during IVM.
authors.affiliation: Institute of Reproductive and Developmental Biology, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom.
authors.forename: Ruth
authors.initials: R
authors.lastname: Roberts
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Iatropoulou
authors.forename: Daniel
authors.initials: D
authors.lastname: Ciantar
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Stark
authors.forename: David L
authors.initials: DL
authors.lastname: Becker
authors.forename: Stephen
authors.initials: S
authors.lastname: Franks
authors.forename: Kate
authors.initials: K
authors.lastname: Hardy
mesh_terms: D000782:Aneuploidy; D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D020090:Chromosome Segregation / Q000187:drug effects; D002875:Chromosomes / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D021621:Imaging, Three-Dimensional; D008677:Metaphase / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D008941:Spindle Apparatus / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure
chemical_list: D005640:Follicle Stimulating Hormone