鼠胚研究顯示
M1(未完全成熟)卵子可有效玻璃化冷凍
不管冷凍前IVM或冷凍後IVM均可達不錯囊胚率 (32% or 28%)
(新鮮M2 囊胚率 56%)

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.

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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.