Hum. Reprod. Advance Access originally published online on December 23, 2008
Human Reproduction 2009 24(4):929-935; doi:10.1093/humrep/den429
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Rhesus macaque embryos derived from MI oocytes maturing after retrieval display high rates of chromosomal anomalies
1 Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA 2 Department of Obstetrics and Gynecology, School of Medicine, Wayne State University, Detroit, MI, USA 3 Department of Anatomy and Cell Biology, School of Medicine, Wayne State University, Detroit, MI, USA 4 Caribbean Primate Research Center, Sabana Seca, Puerto Rico 5 Program in Reproductive and Adult Endocrinology, NICHD, NIH, DHHS, Bethesda, MD, USA
6 Correspondence address. E-mail: cdupont{at}med.wayne.edu
BACKGROUND: Rhesus macaque and human preimplantation embryos display similar rates of chromosomal abnormalities. The aim of this study was to determine whether embryos developing from MI oocytes that mature post-retrieval display more chromosomal anomalies than those embryos that are generated from oocytes that are at MII at the time of retrieval.
METHODS: Rhesus macaque oocytes were obtained after hormonal ovarian stimulation. Immediately after retrieval, the oocytes were classified according to their maturational status. Following in vitro fertilization, Day 3 embryos with good morphology and development derived from oocytes maturing post-retrieval and those from oocytes that were mature at the time of retrieval were cytogenetically assessed using a five-color fluorescent in situ fluorescent hybridization assay developed for rhesus macaque chromosomes homologous to human chromosomes 13, 16, 18, X and Y.
RESULTS: Blastomeres from 53 embryos were analyzed. Of the 27 embryos that developed from oocytes that were mature at collection, 18 embryos were chromosomally normal (66.7%), while from the 26 embryos that developed from oocytes that matured post-retrieval, only 9 embryos were chromosomally normal (34.6%).
CONCLUSIONS: These results indicate that embryos developing from oocytes maturing post-retrieval display high rates of chromosomal abnormalities and have therefore a reduced developmental competence. As a result, the clinical relevance of using immature oocytes that are retrieved after stimulated cycles in human IVF warrants further investigation.
Key words: aneuploidy/embryo/FISH/in vitro maturation/monkey
Submitted on August 4, 2008; resubmitted on October 24, 2008; accepted on November 5, 2008.