Intracytoplasmic sperm injection and embryo development of human oocytes cryopreserved using 1,2-propanediol.
This study reports the subsequent embryo development of cryopreserved mature human oocytes following insemination or intracytoplasmic sperm injection (ICSI). Metaphase II oocytes were cryopreserved using a slow freezing-rapid thawing procedure employing the cryoprotectant 1,2-propanediol. The study was conducted at two centres. The normal insemination of cryopreserved oocytes was undertaken in one centre, and ICSI of cryopreserved oocytes in the other. Both methods resulted in a 50% normal fertilization rate. A low rate of abnormal fertilization was observed in the inseminated group of oocytes (5%) compared with 21% for the ICSI oocytes; this was not significantly different. Embryo development was assessed daily for 7 days. All normal fertilized cryopreserved oocytes in both groups cleaved on day 2, with a similar appearance to in-vitro fertilization and ICSI embryos. In the normal inseminated oocytes, there was a significant decrease in the number of embryos cleaving on day 3 (33%) compared with the development of ICSI oocytes, with a subsequent gradual reduction over days 4 and 5 (22 and 11% respectively) resulting in one early blastocyst on day 7 (11%). In contrast, all ICSI-generated embryos continued to cleave on day 3, with a gradual reduction over subsequent days (day 4, 86%; day 5, 57%; day 6, 43%; day 7, 29%). By day 7, two of the blastocysts had started to hatch, resulting in a 66% hatching rate of blastocysts formed from ICSI of cryopreserved oocytes. This is the first study to show normal development to the hatching blastocyst stage following ICSI of cryopreserved human oocytes.
Gook
D A
DA
Reproductive Biology Unit, Royal Women's Hospital, Carlton, Victoria, Australia.
Schiewe
M C
MC
Osborn
S M
SM
Asch
R H
RH
Jansen
R P
RP
Johnston
W I
WI
D001755:Blastocyst / Q000502:physiology; D002970:Cleavage Stage, Ovum; D015925:Cryopreservation; D003451:Cryoprotective Agents; D003593:Cytoplasm; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D008845:Microinjections; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D019946:Propylene Glycol; D011409:Propylene Glycols
D003451:Cryoprotective Agents; D011409:Propylene Glycols; D019946:Propylene Glycol