The effects of activated-omental extract on nuclear and cytoplasmic in vitro maturation of rat oocytes

Objective: The role of growth factors, including vascular endothelial growth factor of activated omentum on mitosis is clearly known, though not on all the aspects of in vitro oocyte maturation. This study was designed to assess the effect of activated-omental extract (AOE) on in vitro maturation (IVM) of rat cumulus-oocyte complexes (COCs). Materials and Methods: In this experimental study, the COCs were incubated in Ham’s F-۱۰ supplemented with either ۲۰% AOE, ۲۰% fetal bovine serum (FBS) or serum-free media. Post-culture COCs were studied according to the cumulus cells (CCs) expansion, nuclear maturation and cytoplasmic maturation. Cumuli expansion was evaluated by inverted microscope without staining; nuclear maturation was assessed by aceto-orcein staining (light microscope) and cytoplasmic maturation was also observed by TEM. Results: Expansion of CCs and nuclear maturation of the oocytes in in vitro for ۲۴ hr was significantly higher in AOE- and FBS-supplemented groups (P=۰.۰۰۰ and ۰.۰۱۳) and (P=۰.۰۰۴ and ۰.۰۱۴), respectively, compared to serum-free group. At ultra-structural level, after ۲۴ hr, both FBS and AOE-supplemented media showed uniformly wide perivitelline space (PVS). After ۱۲ hr, the cortical granules were found in the oocytes cultured in FBS and AOE-supplemented media. Within ۲۴ hr, both granules and mitochondria were large without any detectable topographic tendency across the ooplasm. In AOE and FBS- supplemented oocytes, the number and size of microvilli were more than those in serum-free one. Conclusion: Although AOE supplementation induced a higher rate of the CCs expansion, and resuming meiosis, it was not as potent as FBS to provide cytoplasmic maturation of rat oocytes.

کلیدواژه ها:

Cumulus cells ، Cytoplasm ، In vitro oocyte maturation ، Nucleus ، Omentum ، Rats