Evaluation of the spindle apparatus of in-vitro matured human oocytes following cryopreservation.
The present study was conducted to determine if the cryopreservation of immature human oocytes has a deleterious effect on the meiotic spindle following maturation in vitro. Oocytes were obtained in excess from in-vitro fertilization patients and divided into four groups. Groups 1 (n = 98) and 2 (n = 80) consisted of immature oocytes cryopreserved before or after maturation in vitro respectively. Groups 3 (n = 37) and 4 (n = 9) served as non-frozen controls and included oocytes matured in vitro and in vivo respectively. The meiotic spindle was identified after incubation in anti-tubulin monoclonal antibody (1 h, 37 degrees C) and fluorescein-conjugated goat anti-mouse immunoglobulin G (IgG) (1 h, RT). Chromosomes were counterstained with 4',6'-diamidino-2-phenylindole. Following cryopreservation, group 1 oocytes demonstrated a 63% survival rate and 68% maturation rate in vitro. In all, 58% of the oocytes in group 2 survived the thaw. The number of oocytes with normal spindles in group 1 (81.0%) was not significantly different from control groups 3 (83.8%) and 4 (88.9%), while the number of group 2 oocytes with normal structures (43.5%) was significantly lower than groups 1 (P = 0.0004), 3 (P = 0.0002), and 4 (P = 0.025). These results suggest that cryopreservation of the prophase I human oocyte does not significantly increase abnormalities in the resulting meiotic spindle.
Baka
S G
SG
Massachusetts General Hospital, Boston, USA.
Toth
T L
TL
Veeck
L L
LL
Jones
H W
HW
Muasher
S J
SJ
Lanzendorf
S E
SE
D002470:Cell Survival; D002478:Cells, Cultured; D016922:Cellular Senescence; D002875:Chromosomes / Q000648:ultrastructure; D015925:Cryopreservation; D005455:Fluorescent Antibody Technique; D006801:Humans; D009865:Oocytes / Q000502:physiology* / Q000648:ultrastructure; D008941:Spindle Apparatus / Q000502:physiology* / Q000648:ultrastructure