Study On In Vitro Maturation And In Vitro Fertilization Of Mice Denuded Oocytes

This study use mice denuded oocytes as object. Firstly, it compares denudedoocytes'maturation rates, fertilization rates and embryos development rates withcumulus-oocyte complex's in different maturational mediums. Secondly, this paperuse sperm subzonal (perivitelline space) insemination (SUZI) method to discuss theeffects of zona pellucida on denuded oocytes'fertilization. Thirdly, this paper usetransmission electron microscope to analyze the changes during denuded oocytesmaturation process in ultrastructure level. The results shown as follow:1. The study on mice denuded oocytes'in vitro maturation, in vitro fertilizationand in vitro development.This part of paper is to discuss whether the remove of granulose cells can affect the mice oocytes maturation rates, fertilization rates and development rates in vitro.The results indicate that:(1) For consuetudinary maturation culture mediums, such as M199 andα-MEM,the maturation rates of denuded oocytes are significantly lower than Cumulus-oocytecomplex's.(2) Using different maturation culture mediums can improve the maturation ratessignificantly.(3) Denude oocytes matured in vitro have a clearly deficiency on fertilization invitro.(4) Remove of granulose cells before maturation will do no harm to earlyembryonic development.2. The sperm subzonal (perivitelline space) insemination on mice denudedoocytes.This part of paper use SUZI method to investigate the effects of zona pellucidaon denuded oocytes'fertilization. The results indicate that:(1) Using SUZI method can improve the fertilization rates of denuded oocytessignificantly. This result suggests zona pellucida may be one of the reasons that makedenude oocytes matured in vitro have a clearly deficiency on fertilization in vitro.(2) For consuetudinary maturation culture mediums, such as M199 andα-MEM,the SUZI fertilization rates of denuded oocytes are significantly lower thanthe Cumulus-oocyte complex's. It indicates that there are other reasons that makedenude oocytes matured in vitro have a clearly deficiency on fertilization in vitro besides zona pellucida.(4) Remove of granulose cells before maturation will do no harm to earlyembryonic development derived from SUZI.3. The changes during denuded oocytes maturation process in ultrastructurelevel.Remove of granulose cells before maturation will decrease the maturationquality. In order to find the reason, this part of paper use transmission electronmicroscope to analyze the changes during denuded oocytes maturation process inultrastructure level. The results indicate that:(1) The changes of microvilli during denuded oocyte mature process in vitro areconform to the changes in cumulus-oocyte complex.(2) The changes of mitochondria during denuded oocyte mature process in vitroare conform to the changes in cumulus-oocyte complex.(3) During denuded mice oocyte mature process in vitro, the cortical granulesmay have abnormal numbers or generation problems. This may be another reason thatmakes denude oocytes matured in vitro have a clearly deficiency on fertilization invitro.