Related Experiment Video
Updated: Jun 17, 2026
08:00
Defining the Program of Maternal mRNA Translation during In vitro Maturation using a Single Oocyte Reporter Assay
Published on: June 16, 2021
Oocyte in-vitro maturation: BCL2 mRNA content in cumulus cells reflects oocyte competency
M Filali1, N Frydman, M P Belot
1APHP, Service d'Histologie Embryologie Cytogénétique, Hôpital Antoine Béclère, Clamart, F-92140, France.
Reproductive Biomedicine Online
|December 26, 2009
Summary
Higher BCL2 expression in cumulus cells correlates with oocyte maturation and fertilization success in women with PCOS undergoing in-vitro maturation (IVM). BAX levels did not show significant variation.
Area of Science:
- Reproductive biology
- Cellular apoptosis
- Ovarian physiology
Background:
- The BCL2 gene family, including BCL2-associated X protein (BAX) and B-cell leukaemia/lymphoma gene-2 (BCL2), regulates apoptosis.
- Previous studies suggested a link between cumulus cell apoptosis and oocyte maturation during ovarian stimulation.
- Limited data exists on this relationship in unprimed ovaries, particularly in women with polycystic ovary syndrome (PCOS).
Purpose of the Study:
- To investigate the impact of BAX and BCL2 expression in cumulus cells on the competency of in-vitro matured oocytes.
- To explore the association between BCL2 and BAX mRNA levels and oocyte maturation and fertilization rates in women with PCOS.
Main Methods:
- Analysis of 100 cumulus-oocyte-complexes (COC) from 13 women with PCOS undergoing in-vitro maturation (IVM).
- Measurement of BAX and BCL2 mRNA content in cumulus cells using real-time polymerase chain reaction after 24-hour maturation.
- Correlation of mRNA levels with oocyte maturation status and fertilization outcomes.
Main Results:
- BCL2 mRNA expression was significantly higher in cumulus cells surrounding mature oocytes compared to immature oocytes.
- BAX mRNA concentrations did not significantly differ between cumulus cells of mature and immature oocytes.
- Higher BCL2 mRNA content was observed in cumulus cells of successfully fertilized oocytes.
Conclusions:
- BCL2 expression in cumulus cells is strongly associated with the oocyte's ability to achieve nuclear maturation.
- Elevated BCL2 mRNA levels in cumulus cells correlate with successful oocyte fertilization.
- These findings highlight the role of BCL2 in oocyte developmental competence during IVM in women with PCOS.
Related Concept Videos
02:07Oogenesis
In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from the equivalent procedure of spermatogenesis in males. First, meiotic divisions during oogenesis are asymmetric, meaning that a large oocyte (containing most of the cytoplasm) and minor polar body are produced as a result of meiosis I, and again following meiosis II. Since only oocytes will go on to form embryos if fertilized, this unequal...
01:22Oogenesis
Oogenesis, the process of developing egg cells (female gametes), occurs within the ovaries and is fundamental to female fertility. This sequence begins during fetal development when diploid oogonia in the developing ovaries undergo mitotic divisions to produce primary oocytes. By birth, these primary oocytes enter prophase I of meiosis but become arrested in this stage, remaining suspended until puberty.
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
01:20Folliculogenesis
Folliculogenesis is the development of ovarian follicles, the specialized structures within the ovarian cortex where oogenesis, or egg development, occurs. This process is essential for female reproductive health and begins during fetal development when primordial follicles are formed. Each primordial follicle comprises a primary oocyte in the center, surrounded by a single layer of squamous pre-granulosa cells. These follicles remain dormant in late prophase I of meiosis until triggered by...