Pigment epithelium-derived factor (PEDF) plays a role in oocyte quality
2IVF and Fertility Unit, Department of OB\GYN, Assaf Harofeh Medical Center, Zerifin; Sackler Faculty of Medicine, Tel Aviv University, Israel
Molecular changes, caused by various environmental factors, affect oocyte quality and developmental potential. Elevated oxidative stress (OS) is a major factor, which is prevalent in various gynecologic disorders and/or in aging. Recent studies suggest that elevated reactive oxygen species (ROS) hamper oocyte metabolism, quality, as well as embryonic development. Pigment epithelium-derived factor (PEDF) is a pleiotropic protein, known for its anti-angiogenic, anti-inflammatory and anti-oxidative properties. Our previous findings demonstrate the anti-oxidative role of PEDF in maintaining granulosa cells viability. In the current study, our aim was to examine the ability of PEDF to negate the adverse impact of OS on oocytes.
Mouse germinal vesicle (GV) oocytes were exposed for one hour to various concentrations of H2O2 (50-150µM) in the presence or absence of 5nM recombinant PEDF (rPEDF). Using confocal microscopy, we assessed oocyte spindle orientation and metaphase II chromosomes. We used qPCR to analyze the number of mitochondrial DNA (mtDNA) copies in a single oocyte and measured its mitochondrial potential.
Oocytes exposed to H2O2 exhibited delayed and/or hampered maturation. The membrane potential of their mitochondria was reduced, whereas supplementation of rPEDF ameliorated the impact of OS on oocyte maturation. Additionally, rPEDF rescued the mtDNA from the adverse effect of OS on their copy number, and reduced the damage reflected by their membrane potential. Moreover, PEDF protected oocytes from OS, as demonstrated by assessing the spindle position and metaphase integrity in each oocyte.
Our study indicates that PEDF has a protective anti-oxidative effect on oocytes. under OS conditions.
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