Storage time does not modify the gene expression profile of cryopreserved human metaphase II oocytes

ABSTRACT: Study question: Does storage time impact on transcriptome of slowly frozen cryopreserved human metaphase II (MII) oocytes? Summary answer: For the first time, we demonstrate that the length of cryostorage has no effect on the gene expression profile of human metaphase II oocytes. What is known already: Oocyte cryopreservation is a largely-used technique in IVF for storage of surplus oocytes, as well as for fertility preservation (i.e., women undergoing gonadotoxic therapies) and oocyte donation programs. Although it is known that cryopreservation negatively impacts on oocyte physiology and it is associated with decrease of transcripts, no experimental data about the effect of storage time on the oocyte molecular profile are available to date. Study design, size, duration: This study included 27 women undergoing IVF treatment, < 38 years aged, without any ovarian pathology. Surplus MII oocytes were donated after written informed consent. A total of 31 non-cryopreserved oocytes and 68 surviving slow-frozen/rapid-thawed oocytes (32 oocytes cryostored for 3 years and 36 cryostored for 6 years) were analyzed. Participants/materials, setting, methods: Pools of ≈10 oocytes for each group were prepared. Total RNA was extracted from each pool, amplified, labeled and hybridized on 4x44K v2 microarrays (Agilent). Analyses were performed by R v3.1.3 software using the limma package v3.22.7. Main results and the role of chance: Comparison of gene expression profiles between surviving thawed oocytes after 3 and 6 years of storage in liquid nitrogen found no differently expressed genes. The expression profiles of cryopreserved MII oocytes significantly differed from those of non-cryopreserved oocytes in 107 probe sets corresponding to 73 down-regulated and 29 up-regulated unique transcripts. Gene Ontology analysis by DAVID bioinformatics resource disclosed that cryopreservation deregulates genes involved in oocyte function and early embryo development, such as chromosome organization, RNA splicing and processing, cell cycle process, response to DNA damage stimulus, cellular response to stress and DNA repair, calcium ion binding, malate dehydrogenase activity, mitochondrial membrane respiratory chain. Among the probes significantly up-regulated in cryopreserved oocytes, 2 corresponded to ovary-specific expressed large intergenic noncoding (linc)RNAs.

ORGANISM(S): Homo sapiens

PROVIDER: GSE69768 | GEO | 2015/09/19

SECONDARY ACCESSION(S): PRJNA286734

REPOSITORIES: GEO