title: Effects of embryo culture media do not persist after implantation: a histological study in mice.
abstract: OBJECTIVE
  Is post-implantation embryonic development after blastocyst transfer affected by exposure to different assisted reproduction technology (ART) culture media?
  
  
  CONCLUSIONS
  Fetal development and placental histology of ART embryos cultured in vitro in different ART media was not impaired compared with embryos grown in vivo.
  
  
  BACKGROUND
  The application of different in vitro culture (IVC) media for human ART has an effect on birthweight of newborns. In the mouse model, differences in blastocyst formation were reported after culture in different ART media. Moreover, abnormalities in the liver and heart have been detected as a result of suboptimal IVC conditions.
  
  
  METHODS
  Fertilized oocytes from inbred and outbred breeding schemes were retrieved and either immediately transferred to foster mothers or incubated in control or human ART culture media up to the blastocyst stage prior to transfer. Placental and fetal anatomy and particularly bone development were evaluated.
  
  
  METHODS
  B6C3F1 female mice were used as oocyte donors after ovulation induction. C57Bl/6 and CD1 males were used for mating and CD1 females as foster mothers for embryo transfer. Fertilized oocytes were recovered from mated females and incubated in sequential human ART media (ISM1/ISM2 and HTF/Multiblast), in control media [KSOM(aa) and Whitten's medium] or grown in utero without IVC (zygote control). As in vivo, control B6C3F1 females were superovulated and left untreated. Fetuses and placentae were isolated by Caesarean section and analysed at 18.5 days post-coitum (dpc) for placenta composition and at 15.5 dpc for body weight, crown-rump length (CRL), fetal organ development, morphological development, total bone length and extent of bone ossification.
  
  
  RESULTS
  No major differences in the number of implantation sites or in histological appearance of the placentae were detected. CRL of KSOM(aa) fetuses was higher compared with zygote control and Whitten's medium. Histological analysis of tissue sections revealed no gross morphological differences compared with the in vitro groups or in vivo controls. Furthermore, no changes in skeletal development and degree of ossification were observed. However, fibula and tibia of ISM1/ISM2 fetuses were longer than the respective ones from in vivo fetuses.
  
  
  CONCLUSIONS
  Findings in the mouse embryo and fetus may not be fully transferable to humans. In addition to skeletal development and placentation, there may be other parameters, e.g. on the molecular level which respond to IVC in ART media. Some comparisons have limited statistical power.
  
  
  CONCLUSIONS
  Our data suggest that once implantation is achieved, subsequent post-implantation development unfolds normally, resulting in healthy fetuses. With mouse models, we gather information for the safety of human ART culture media. Our mouse study is reassuring for the safety of ART conditions on human embryonic development, given the lack of bold detrimental effects observed in the mouse model.
  
  
  BACKGROUND
  This work was supported by the Deutsche Forschungsgemeinschaft (BO 2540/4-1 and SCHL 394/9-1) and by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (S.L.G.); Bilateral grant NWO-DFG 63-258. None of the authors has any conflict of interest to declare.
  
  
  BACKGROUND
  Not applicable.
authors: Institute for Molecular Cell Biology, Westfalian Wilhelms University Münster, Schlossplatz 5, 48149 Münster, Germany.
authors: Sandra A
authors: SA
authors: Hemkemeyer
authors: Caroline
authors: C
authors: Schwarzer
authors: Michele
authors: M
authors: Boiani
authors: Jens
authors: J
authors: Ehmcke
authors: Séverine
authors: S
authors: Le Gac
authors: Stefan
authors: S
authors: Schlatt
authors: Verena
authors: V
authors: Nordhoff
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology; D001842:Bone and Bones / Q000196:embryology; D002356:Cartilage / Q000196:embryology; D003470:Culture Media / Q000737:chemistry*; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D008099:Liver / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009206:Myocardium / Q000378:metabolism; D009865:Oocytes / Q000166:cytology; D011247:Pregnancy; D011270:Pregnancy, Animal; D027724:Reproductive Techniques, Assisted / Q000295:instrumentation*
chemical_list: D003470:Culture Media
keywords: ART culture media; MEA; bones; murine fetal development; placenta