不成熟卵子(M1)先施予IVM達成熟狀態(M2)再冷凍解凍[IVM>vitriciation>thawing>ICSI]
懷孕率高於
不成熟卵子(M1)先冷凍解凍再IVM達M2狀態[vitriciation>thawing>IVM>ICSI]

冷凍過程會影響不成熟卵子之IVM比例(84%>68%)

PLoS One. 2016 Jun 22;11(6):e0157785. doi: 10.1371/journal.pone.0157785. eCollection 2016.

Production of Live Offspring from Vitrified-Warmed Oocytes Collected at Metaphase I Stage.

Chang CC1, Chang WF2, Xu J3, Cheng AS4, Chang CC2, Nagy ZP1, Yang CC5, Ding ST2,6, Sung LY2,7,8.

Author information

Abstract

Vitrification of matured oocytes is widely adopted in human clinics and animal research laboratories. Cryopreservation of immature oocytes, particularly those at metaphase I (MI), remains a challenge. In the present work, mouse MI oocytes denuded of cumulus cells were vitrified and warmed (V/W) either prior to (V/W-BEFORE-IVM, n = 562) or after (V/W-AFTER-IVM, n = 664) in vitro maturation (IVM). Derivative metaphase II (MII) oocytes were then used for intracytoplasmic sperm injection (ICSI). In the control groups, in vivo matured MII oocytes were used freshly (FRESH-MII, n = 517) or after V/W (MII-V/W, n = 617). In vitro and in vivo developmental competencies were compared among groups. Satisfactory blastocyst rates were achieved in V/W-BEFORE-IVM (27.5%) and V/W-AFTER-IVM (32.4%) groups, albeit as expected still lower than those from fresh-MII (56.1%) or MII-V/W (45.6%) oocytes. Similarly, the term development rates from V/W-BEFORE-IVM and V/W-AFTER-IVM were 12.4% and 16.7% respectively, acceptable but lower than those of the fresh-MII (41.2%) and MII-V/W (23.3%) groups. These data demonstrate that oocytes collected at MI stage are amenable to V/W, which can be performed before or after IVM with acceptable development rates including production of healthy pups. These findings provide useful knowledge to researchers and clinical practitioners for preservation and use of the otherwise discarded MI oocytes.

Table 1

In vitro development of vitrified oocytes after ICSI.

Group	No. of replicates	No. of starting MI oocytes	No. of MI oocytes survived post warming (% of per MI oocyte)	No. of available MII oocytes (% of per MI oocyte)	No. of oocytes survived post warming (% of per MII oocyte)	No. of available IVM MI-II oocytes post warming (% of per MI oocyte)	No. of oocytes survived post ICSI (% of per MII oocyte)	No. of cleaved embryos (% of per MII oocyte)	No. of blastocysts (% of per MII oocyte)
FRESH-MII (Control 1)	6	N/A	N/A	517	N/A	N/A	378 (73.3)a	376 (72.8)a	290 (56.1)a
MII-V/W (Control 2)	8	N/A	N/A	617	589 (95.3)a	N/A	344 (56.4)b	341 (55.8)b	274 (45.6)b
V/W-AFTER-IVM	9	790	N/A	664 (84.1)a	644 (96.8)a	644 (81.5) a	339 (50.7)b	323 (48.3)bc	216 (32.4)c
V/W-BEFORE-IVM	8	818	756 (92.4)	562 (68.7)b	N/A	562 (68.7) b	259 (45.9)b	252 (44.6)c	158 (27.5)c

Percentage data were arcsine transformed and subjected to Tukey's multiple comparisons test using Graphpad Prism (v6.02).

a, b, c different superscripts within the same column indicates statistical difference (P<0.05).