Mouse ovarian follicle cryopreservation using vitrification or slow programmed cooling: Assessment of in vitro development, maturation, ultra-structure and meiotic spindle organization

作者：Desai Nina^*; AbdelHafez Faten; Ali Mansour Y; Sayed Ezzat H; Abu Alhassan Ahmed M; Falcone Tomasso; Goldfarb James

来源：Journal of Obstetrics and Gynaecology Research, 2011, 37(1): 1-12.

DOI：10.1111/j.1447-0756.2010.01215.x

• in vitro maturation
• meiotic spindle retardance
• pre-antral follicle
• ultra-structure
• vitrification

Aim:
To compare different outcomes of vitrification and slow freezing of isolated pre-antral follicles and to evaluate different cryo-devices for vitrification of isolated follicles.
Methods:
Pre-antral follicles were isolated from mouse ovaries and cryopreserved using vitrification and slow freezing. A preliminary experiment was carried out to select the optimal cryo-device for vitrification of isolated follicles. A total of 414 follicles were randomly distributed among four groups: control (CT) fresh (n = 100), nylon mesh (n = 96), electron microscopy grid (n = 102), and micro-capillary tips (n = 116). Subsequently, a total of 979 follicles were randomly assigned to three different groups: CT fresh (n = 256), vitrification (n = 399) and slow freezing (n = 324). CT and cryopreserved/thawed follicles were cultured in vitro and examined daily for development. Final maturation was triggered with human chorionic gonadotrophin and rates of oocyte maturation were calculated. The ultra-structure of cryopreserved/thawed follicles was studied using electron microscopy. Meiotic spindle presence and organization in mature oocytes were examined using the Oosight imaging system.
Results:
Micro-capillary tips resulted in poor immediate post-warming survival but no differences were observed in the subsequent in vitro development characteristics between different cryo-devices. Nylon mesh proved to be the easiest carrier, particularly when large numbers of follicles were to be vitrified. Compared to vitrification, slow freezing resulted in a significantly lower number of intact follicles at the end of the culture period (P < 0.0001). However all other outcome measures were comparable between both techniques.
Conclusions:
Isolated follicles were more vulnerable to cryodamage after slow freezing as compared to vitrification.

• 出版日期2011-1