Study and applications of human oocyte cryopreservation
- VernacularTitle:人卵母细胞冻融的研究与应用
- Author:
Xiaohong LI
- Publication Type:Journal Article
- Keywords:
Oocytes;
Cryopreservation;
Fertilization in vitro;
Meiosis;
Vitrification
- From:
Journal of Peking University(Health Sciences)
2003;0(06):-
- CountryChina
- Language:Chinese
-
Abstract:
The oocyte cryopreservation is more promising than embryo freezing in clinical applications,preservation of female fertility,legal and ethical aspects in this decade.The redundant oocytes retrievedfrom ⅣF cycles can potentially donate oocytes,which have unique advantages in economy and feasibili-ty.We have achieved success in embryo freezing,but just obtained poorer results in oocyte cryopreserva-tion which was mainly because of the low rates of survival,fertilization,and cleavage.The character ofthe plasma membrane and the time of cortical granules present at the metaphase of meiosis Ⅱ with thespindle system consist of the major difference between oocytes and embryos.Moreover,the oocytes shouldbe fertilized by sperm at the appropriate time.We used a refined slow freezing method to improve the sur-vival rate and increased sucrose concentration to dehydrate oocytes.Vitrification was another approach toprevent harms.Besides,intracytoplasmic sperm injection was used to overcome possible zona hardeningafter the release of cortical granules.Oocytes after cryopreservation showed serious disturbances of the mi-crotubules immediately after thawing as they were vulnerable to the thermal changes and easy to depoly-merize.Fertilization of these oocytes with disorganized spindles led to chromosomal aneuploidy,digyny,and degradation of the cleavage rate.We can improve cryopreserved oocytes to normal fertilization anddevelopment by appropriate incubation and timing of insemination,as the microtubules repolymerize in atime dependent way after incubation which is compatible with recovery of the spindles.With the improve-ment of survival,fertilization,and development,oocyte cryopreservation will play an imperative role.
