Cryopreservation of human germinal vesicle stage and in vitro matured M IIoocytes: influence of cryopreservation media on the survival, fertilization, and early cleavage divisions
A. Goud et al., Cryopreservation of human germinal vesicle stage and in vitro matured M IIoocytes: influence of cryopreservation media on the survival, fertilization, and early cleavage divisions, FERT STERIL, 74(3), 2000, pp. 487-494
Objective: To study the influence of low-sodium cryopreservation media (CPM
) on the survival and development of frozen-thawed germinal vesicle (GV) st
age and in vitro matured human oocytes.
Design: Prospective experimental study.
Setting: Academic hospital-based fertility center.
Patient(s): Experimental groups: Oocytes cryopreserved at the GV (group A,
n = 63 and group B, n = 64) or M II stage (group C, n = 62) With use Of con
ventional (group A) or low-sodium CPM (groups B and C). Control groups: Sib
ling GV stage oocytes subjected to in vitro maturation (IVM; control group
A, n = 64; control group B, n = 64).
Intervention(s): IVM, intracytoplasmic sperm injection and subsequent cultu
re.
Main Outcome Measure(s): Rates of survival, maturation, fertilization, and
cleavage.
Result(s): The postthaw survival was significantly lower in groups A (57.1%
) and B (48.4%) compared to C (84.4%). In group A, maturation and cleavage
rates were significantly lower, and fertilization rate was similar to contr
ols (GVBD: 72.2% vs. 90.6%; progression to M II: 33.3% vs. 76.6%; cleavage:
42.9% vs. 88.2%; and fertilization: 58.3% vs. 69.4% in group A vs, control
group A, respectively). There was no such difference in group B. In group
C, despite a slight but significant lowering of the rate of 2 PN and an inc
rease in that of 3 PN (2 PN: 47.4% vs. 70.2% and 3 PN: 15.8% vs. 3.2% in gr
oup C vs. total controls, respectively), embryonic cleavage per GV oocyte w
as significantly higher (25.8%) compared to group A (4.8%) but not to group
B (15.6%). The rate of maturation and cleavage per surviving GV oocyte was
significantly higher in group B than group A.
Conclusion(s): Low-sodium-based CPM is beneficial for in vitro matured M II
stage oocytes and is significantly better than the conventional sodium-bas
ed media for the GV stage oocytes. (Fertil Steril(R) 2000; 74:487-93. (C) 2
000 by American Society for Reproductive Medicine.).