Differences in cumulus cells gene expression between modified natural and stimulated in vitro fertilization cycles.
OBJECTIVE
The aim of our study was to determine whether there are any differences in the cumulus cell gene expression profile of mature oocytes derived from modified natural IVF and controlled ovarian hyperstimulation cycles and if these changes could help us understand why modified natural IVF has lower success rates.


METHODS
Cumulus cells surrounding mature oocytes that developed to morulae or blastocysts on day 5 after oocyte retrieval were submitted to microarray analysis. The obtained data were then validated using quantitative real-time PCR.


RESULTS
There were 66 differentially expressed genes between cumulus cells of modified natural IVF and controlled ovarian hyperstimulation cycles. Gene ontology analysis revealed the oxidation-reduction process, glutathione metabolic process, xenobiotic metabolic process and gene expression were significantly enriched biological processes in MNIVF cycles. Among differentially expressed genes we observed a large group of small nucleolar RNA's whose role in folliculogenesis has not yet been established.


CONCLUSIONS
The increased expression of genes involved in the oxidation-reduction process probably points to hypoxic conditions in modified natural IVF cycles. This finding opens up new perspectives for the establishment of the potential role that oxidation-reduction processes have in determining success rates of modified natural IVF.
Department of Human Reproduction, Division of Gynecology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
Tanja Burnik
TB
Papler
Eda Vrtačnik
EV
Bokal
Klementina Fon
KF
Tacer
Peter
P
Juvan
Irma
I
Virant Klun
Rok
R
Devjak
D000328:Adult; D054885:Cumulus Cells / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000235:genetics*; D005307:Fertilization in Vitro; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D054315:Oocyte Retrieval; D010062:Ovulation Induction; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000235:genetics; D018873:Pregnancy Rate; D059467:Transcriptome