Effects Of Pineal Peptide Epitalon On Mouse Oocyte Aging

Objective:In mammals,oocyte maturation is a highly specialized process regulated by a number of factors,culminating in simultaneous maturation of the nucleus and cytoplasm before oocytes have the potential to develop.Healthy offspring are usually produced by fertilization of fresh oocytes with sperm.Mature oocytes or abnormal development of oocyte fertilization not only affect the fertilization rate,but also affect embryonic development after implantation of potential,a lot of assisted reproductive technology(ART)failures are related to the quality of oocytes,the purpose of this study was to add Epitalon by in vitro culture medium to explore its influence on oocyte aging.Methods:1.The aged oocyte model was established and the changes of cytoplasm,spindle and cortical granules were detected.2.Cell damage caused by oxidative stress in the aging oocytes were detected: reactive oxygen species level,mitochondrial membrane potential,mitochondrial copy number.3.The apoptosis indexes of oocytes in the aging process were measured: phosphatidylserine eversion and fluorescence intensity of γH2AX.Results:1.Cytoplasm fragmentation,abnormal spindle morphology and exocytosis of cortical granules were observed in mouse mature oocytes cultured in vitro.2.The fresh group,aging group and Epitalon group were compared respectively,and it was found that adding 0.1m M Epitalon in vitro culture medium could reduce the ratio of cytoplasm fragmentation and intracellular reactive oxygen species content caused by oocyte aging to a certain extent.3.The rate of cytoplasmic fragmentation during parthenogenetic activation of oocytes due to aging was reduced by adding 0.1m M Epitalon in vitro medium.4.The rate of abnormal spindle morphology and cortical granular exocytosis could be reduced by adding 0.1m M Epitalon into the in vitro medium.5.The addition of 0.1m M Epitalon in vitro culture medium increased mitochondrial membrane potential,mitochondrial DNA copy number,and decreased phosphatidylserine eversion and γH2AX fluorescence intensity in aged oocytes.Conclusion:1.Mouse mature oocytes will senescence due to the accumulation of reactive oxygen species in vitro.2.By adding different concentrations of Epitalon to the culture medium,it was found that0.1m M could reduce the accumulation of reactive oxygen species in oocytes caused by aging,indicating that this concentration of Epitalon had a certain antioxidant effect,while Epitalon with higher concentration than 2m M could increase the level of intracellular reactive oxygen species,indicating that too high concentration of Epitalon had a certain cytotoxic effect.3.0.1m M Epitalon added to the culture medium in vitro can improve the disorder of organelles during oocyte aging and improve the quality of oocytes.4.0.1m M Epitalon added to the culture medium in vitro reduce the cell damage caused by oxidative stress and delay the process of oocyte aging in vitro.