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Updated: Nov 18, 2025
Vitrification of In Vitro Matured Oocytes Collected from Adult and Prepubertal Ovaries in Sheep
Published on: July 10, 2021
In vitro maturation of Mus musculus mice oocytes after hyperosmotic shock induced by vitrification solutions
Erica Koaski1, Cláudia Schneider Colle1, Rafael Alonso Salvador1
1Universidade do Vale do Itajaí (UNIVALI), Laboratory of Reproductive Biology, Itajaí/SC, Brasil.
Objective:
To evaluate in vitro oocyte maturation rates in embryonic culture medium after induction by hyperosmotic shock caused by exposure to vitrification solutions.
Methods:
Bilateral oophorectomy was performed on 20 prepubescent female mice (Swiss). Immature (Prophase I) oocytes (N = 400) were obtained by ovarian dissection, divided into 4 groups, and transferred to culture dishes containing fertilization medium (Sydney IVF Fertilization Medium, Cook® Medical). The control group (CG) did not receive treatment, the test groups (G1, G2, G3) were treated with vitrification solution - 2 (VI-2: 14 M sucrose + ethylene glycol and dimethyl sulfoxide) for 30 seconds and subsequently: G1: 30 seconds in devitrification solution - 2 (DV-2: 0.5M sucrose); G2: 60 seconds DV-2; G3: 60 seconds DV-1(1M sucrose) and 180 seconds DV-2. All groups were cultivated for 24 hours in an incubator at 37ºC and 5% CO2 (Thermo model 3110). After this period, we checked their maturation status.
Results:
Oocytes exposed to VI-2, DV-1 and DV-2 (G3) showed the highest rate of competence in resuming meiosis and reaching the MII stage; however, there was no statistically significant difference (G3 = 50.5% - 49/97; CG = 27.8% - 10/30).
Conclusions:
Oocyte exposure to vitrification solutions, in order to cause osmotic shock, did not interfere with the resumption of meiosis in mice oocytes.
