Abstract
The oocyte and the surrounding cumulus cells (CCs) are deeply linked by a complex bidirectional cross-talk. In this light, the molecular analysis of the CCs is nowadays considered to be precious in providing information on oocyte quality. It is now clear that miRNAs play a key role in several ovarian functions, such as folliculogenesis, steroidogenesis, and ovulation. Thus, in this study, specific miRNAs, together with their target genes, were selected and investigated in CCs to assess the response of patients with normal (NR) and low (LR) ovarian reserve to two different controlled ovarian stimulation (COS) protocols, based on rFSH and hMG. Moreover, a Fourier transform infrared microspectroscopy (FTIRM) analysis was performed to evaluate DNA conformational changes in CCs and to relate them with the two COS protocols. The results evidenced a modulation of the expression of miRNAs and related target genes involved in CCs’ proliferation, in vasculogenesis, angiogenesis, genomic integrity, and oocyte quality, with different effects according to the ovarian reserve of patients. Moreover, the COS protocols determined differences in DNA conformation and the methylation state. In particular, the results clearly showed that treatment with rFSH is the most appropriate in NR patients with normal ovarian reserve, while treatment with hMG appears to be the most suitable in LR patients with low ovarian reserve.
Highlights
A complex bidirectional communication is observed between the oocyte and the cumulus cells (CCs) that surround it, which have trophic functions, but are involved in the maintenance of the meiotic block of the oocyte during follicular growth [1]
Some differences related to the adopted controlled ovarian stimulation (COS) protocol were detectable: first, in the normal ovarian reserve (NR) group, a significantly higher percentage of fertilized oocytes was found in patients treated with rFSH, with respect to those treated with hMG, while no difference was found with regard to the percentages of mature and immature oocytes; to a further
Protocols modulate the expression of key genes for cumulus cells’ function, with different effects according to the ovarian reserve of patients
Summary
A complex bidirectional communication is observed between the oocyte and the cumulus cells (CCs) that surround it, which have trophic functions, but are involved in the maintenance of the meiotic block of the oocyte during follicular growth [1]. The study of the cumulus-oocyte complex allows one to establish that a ‘competent’ oocyte cannot exist without a ‘competent’ cumulus For this reason, a molecular analysis of the CCs is nowadays considered predictive of oocyte quality [2]. The stage of CC development is associated with the fate of the follicle: their proliferation promotes follicle maturation and ovulation, while their apoptosis causes atresia and follicle degradation [3]. In this light, for proper follicular recruitment, development, and ovulation, somatic and germinal cells within the ovaries need to precisely express specific genes in a coordinated fashion [4]. MicroRNAs (miRNAs) represent a class of small (18–22 nt) non-coding, single-stranded RNAs actively regulating the mRNA translation of over 70%
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
