PurposeThe present study examined the relationships among the amount of cell‐free‐DNA (cfDNA) in porcine follicular fluid (FF), the developmental ability of enclosed oocytes, and characteristics of granulosa cells and examined the effect of cfDNA content in maturation medium on the developmental ability of the oocytes.MethodsOocytes and FF were collected from individual gilts, and the gilts were rated based on the ability of their oocytes to develop to the blastocyst stage and the amount of cfDNA in the FF. The copy numbers of mitochondrial DNA (Mt‐DNA) and nuclear DNA (N‐DNA) were measured by real‐time PCR and the DNA sequence. FF or cfDNA was added to the maturation medium, and the developmental ability of the oocytes was examined.ResultsThe amount of cfDNA was associated with apoptosis of the granulosa cells, and high‐cfDNA content in FF was associated with low developmental ability of oocytes. Supplementation of the maturation medium with FF containing high cf‐Mt‐DNA or with DNA extracted from the FF did not affect oocyte developmental competence.ConclusionsCell‐free DNA content in FF is a marker for oocyte competence, but cfDNA in the oocyte maturation environment did not affect oocyte developmental ability.

We examined age-associated changes in microRNA (miRNA) profiles in the follicular fluid (FF) of cows. The role of miR-19b, which is abundant in the FF of young cows, in in vitro growth of early antral follicles (EAFs)-derived oocytes was assessed. FF was collected from the antral follicles of young (20–40 months) and aged (>120 months) cows. The miRNA profiles were similar between the FF of both age groups, whereas the abundance of some miRNAs differed between these samples. The miRNA profiles in granulosa cells (GCs) and the spent culture medium of oocyte–GC complexes (OGCs) derived from EAFs were distinct. Some miRNA groups overlapped among the GCs, culture media, and FFs. miR-19b was highly abundant in the FF of young cows, GCs and culture medium. The supplementation of OGC culture medium with miR-19b increased the diameter, acetylation levels, and fertilisation ability of the oocytes. To assess whether miR-19b was functional in the GCs, a dual-luciferase assay, suppression of target protein, and RNA-sequencing of the GCs followed by functional annotation of the differentially expressed genes (DEGs) were conducted. Functional annotation of the DEGs suggested that miR-19b influences genes associated with FoxO signalling, endocytosis, and NR3C1 in GCs. These results suggest that in FFs, aging affects the abundance of miRNAs that have important roles in oocyte development.

No abstract

No abstract