OPS vitrification of mouse immature oocytes before or after meiosis: the effect on cumulus cells maintenance and subsequent development.
Cryopreservation can cause cumulus cell damage around the immature oocytes, which may result in poor subsequent development. To evaluate the effect of the meiosis stage on the cumulus cell cryoinjury and determine the suitable stage for cryopreservation in immature oocytes, mouse oocytes at germinal vesicle (GV) and germinal vesicle breakdown (GVBD) stages were vitrified using open pulled straw (OPS) method. Cumulus cells damage was scored immediately after thawing by double-fluorescent staining. The survival rate of the oocytes was evaluated and the subsequent development of oocytes was assessed through in vitro culture (IVC) and in vitro fertilization (IVF) separately. After vitrification, a higher proportion of cumulus cells of GV oocytes were damaged than those of GVBD and untreated control groups. The survival rate of vitrified GVBD oocytes (94.1%) was significantly higher (p < 0.05) than that of GV oocytes (85.4%). Oocytes vitrified at GVBD stage (55.7%) showed similar cleavage rate compared to those at GV stage (49.2%), but significantly higher (p < 0.05) blastocyst rate (40.9% vs. 27.4%). These results demonstrate that oocytes at GVBD stage remain better cumulus membrane integrity and developmental ability during vitrification than those at GV stage, indicating they are more suitable for immature oocytes cryopreservation in mice.
Suo
Lun
L
Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100093, P.R. China.
Zhou
Guang-Bin
GB
Meng
Qing-Gang
QG
Yan
Chang-Liang
CL
Fan
Zhi-Qiang
ZQ
Zhao
Xue-Ming
XM
Fu
Xiang-Wei
XW
Wang
Yan-Ping
YP
Zhang
Qing-Jing
QJ
Zhu
Shi-En
SE
D000818:Animals; D015925:Cryopreservation / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology; D054885:Cumulus Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D008540:Meiosis; D051379:Mice; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*
D003451:Cryoprotective Agents