Cryopreservation of human oocytes and fertilization by two techniques: in-vitro fertilization and intracytoplasmic sperm injection.
Hum Reprod
; 10(10): 2650-4, 1995 Oct.
Article
in En
| MEDLINE
| ID: mdl-8567786
ABSTRACT
Human oocyte cryopreservation results in poor survival and subsequent fertilization rates. It has been suggested that freeze-thaw-induced changes in the zona pellucida may impair sperm penetration or attachment. The aim of this study was to compare fertilization and cleavage rates in cryopreserved oocytes inseminated by conventional in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). A total of 220 oocytes, obtained from volunteers who had undergone ovarian stimulation, were cryopreserved using a slow freeze-rapid thaw protocol with 1.5 M propanediol as the cryoprotectant. Surviving oocytes (n = 74, 34.4%) were randomly allocated for fertilization by conventional IVF (group 1) or ICSI (group 2) using cryopreserved spermatozoa from a single donor of proven fertility. Fertilization was achieved in five (13.5%) of the oocytes in group 1 and 17 (45.9%) in group 2 (P < 0.005), with only one oocyte in group 1 exhibiting normal fertilization as opposed to 16 (43.2%) in group 2 (P < 0.001). Similarly, one oocyte fertilized by IVF cleaved, while all fertilized with ICSI cleaved (P < 0.001). We conclude that although the survival of oocytes is poor following cryopreservation, fertilization and cleavage rates can be enhanced significantly using ICSI. These data also suggest that the method of cryopreservation used in this study affected the zona pellucida, such that normal sperm attachment or penetration was impaired.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oocytes
/
Fertilization in Vitro
/
Cryopreservation
/
Microinjections
Limits:
Female
/
Humans
/
Male
Language:
En
Journal:
Hum Reprod
Year:
1995
Document type:
Article